Guide to defeating Magni the Bison

Magni the Bison
Magni the Bison is a level 24 warrior boss, with all that being a boss entails: very high health (killing him requires dealing around 1300 HP to him), double damage, +3 health regeneration, and half skill activation time. If you don't have any defensive skills but try to trade hits, you'll probably die within ten seconds. As such, any strategy to beat the tournament must start with a way to beat him.

Bison has two knockdown skills, so some of your skills will be interrupted if he hits you. He also has Irresistible Blow, which will knock you down if you block it, so blocking skills don't reduce his knockdowns by much. This means that relatively few builds can invariably beat him, though many can beat him most of the time, so long as you aren't interrupted by one of his knockdowns at a particularly inopportune time.

Furthermore, Bison has Purge Signet which will remove all hexes and conditions from him. He won't use it just to remove crippled or bleeding, but will use it as often as the cooldown allows to remove blindness, weakness, burning, dazed, and/or poison. As such, if you want to keep Bison crippled or bleeding, you may need to eschew the use of the other conditions.

As he is a warrior, if you use a martial weapon, switching to one that does elemental damage can make the battle go faster. This is rarely the difference between winning and losing, but it can substantially shorten the time it takes to defeat him.

There are five basic approaches that reduce Magni's damage enough to usually beat him.

1) Keep him crippled and kill him from a distance.  If done correctly, you can kill Bison without him hitting you, but it relies on exploiting his peculiar AI.  If Bison is not crippled, then he will run straight at you.  If he his crippled, then he will run at you from his starting location, but if you get far enough out of his path, he will turn around and return to his starting location before running out at your new position.  Wait for him to come out, and then head into a corner near Bison's starting location to make him turn around.  Once he goes back, get back out toward the other side of the room and repeat.  If Magni is no longer crippled, he will break off his route and run right at you, so it is critical to keep him crippled for the entire battle.  It can also be useful to add bleeding to negate his natural regeneration, but avoid other conditions so that he doesn't use purge signet.

2) Keep him blinded so he rarely hits you.  Note that you must keep him blinded for essentially the entire battle, as he'll do tremendous damage in any gaps in which he can see you.  As blinding skills often have short durations and long cooldowns, you may need multiple blinding skills to make this work.  That he'll purge blindness is also a problem; you may need to time it so that he purges blindness only when the condition doesn't have much time left.

3) Keep him weakened to limit damage.  Weakness skills can last a while and recharge quickly, but you may still need two weakness skills to account for Bison purging the condition.  If you use one weakness skill and it is immediately purged, you can immediately counter with the other weakness skill, without waiting for the first to come off of cooldown.

4) Keep Protective Spirit on yourself to limit his damage.  You'll have to recast this often, which takes a significant fraction of your energy.  Also beware of Magni's knockdowns, as if he interrupts protective spirit, you're in big trouble, as there isn't an alternate skill with the same effect that you can quickly use.  Protective spirit is a very short cast, so you can safely cast it just after you are hit.  If you ignore Bison's attacking cycle, there is a substantial chance that protective spirit will be interrupted by a knockdown at least once.

5) Bring myriad blocking skills to block most of his attacks.  Blocking skills tend to have very short durations relative to their cooldowns, so you'll probably need several blocking skills to make this work.  Anything below 75% block chance isn't enough to be particularly useful, as you want a 75% or better block chance skill up essentially all of the time.  Some blocking skills will end early under certain conditions, and you may need to be careful not to trigger those conditions and run out of blocking skills not on cooldown.

You will take considerable damage from any of the last four approaches, so you'll need to have a lot of healing available to counteract the damage. In order to avoid running out of energy, you may need to bring substantial energy management or avoid using skills that neither dampen Magni's damage nor heal yourself.

Assembling a build
As you must beat five other opponents in order to reach Bison, any build that can beat him but not the preceding opponents is useless. As such, your build will need to be well-rounded.

Keep in mind that skills whose value lies in the fact that they affect multiple opponents or multiple allies tend to be less useful here, as there is usually only one opponent and only one ally (namely, you). Conversely, skills typically limited by the fact that they only affect one opponent can be highly useful.

The polar opposite of Bison's massive damage with no healing approach is the opponents who have little interest in killing you, but will spam self-heals to try for a stalemate. You'll have to bring skills to either cause a substantial damage spike of 200+ HP within several seconds, or else bring interrupts or some other way to stop their healing.

It is also vital that you bring self-healing skills. Many mobs cannot be finished off before they'll do enough damage to kill you if you can't heal yourself. For several opponents, it is necessary to wait until they are low on energy before you can do much damage, and you'll have to spend a lot of time healing before that.

Health degeneration hexes and conditions are useful, as, unlike a lot of PvE combat where, when you put a 20 second condition on a mob and it dies 5 seconds later, you often get the full duration of health degeneration on the opponent--and if you don't, it usually means you won.

Opponents with interrupts can reliably interrupt skills with an activation time of 1 or more seconds if you don't have a way to prevent them from doing so. Skills with a 3/4 second activation time are only infrequently interrupted. Skills that activate faster than that are pretty safe to cast, and generally interrupted only by dumb luck when an opponent knocks you down without trying to interrupt anything in particular. If you need to get a longer cast off, choose your timing wisely.

A simple trick to increase your maximum health at least a little, is to activate your Norn Title. Even a rank of 1 will provide you with an additional 53 HP.

Earlier tournament opponents
Some opponents are pretty easy to beat with any reasonable build. Here are some tips against the ones that can be hard.

Danika, Sheena, and Brutus
You have to fight all three at once. Danika does virtually no damage, but spams heals on the others. Sheena and Brutus do some damage, but are only level 10. Killing Danika first is probably impractical, but once Sheena and Brutus are dead, finishing off Danika is just a matter of time. Killing Brutus and/or Sheena does not end the match; you have to beat Danika, too.

Zho and Onyx
You fight both at once. Killing Zho wins the match, while killing Onyx doesn't matter. They don't hit very hard, but Onyx will interrupt/disable skills. Focus on Zho, and avoid using vital skills when Onyx activates Disrupting Lunge.

Old Mac and Joe
You fight both at once and killing either one wins the match. If you're playing as a caster, it's often vital that you find a way to avoid Broad Head Arrow (used by Joe).

Kisai, Headmaster Vhang, and Argo
These are three separate fights, but similar in style. Killing them immediately will be impractical for some classes. Focus on keeping yourself alive until they run out of energy, at which point they'll stop casting anything with an energy cost above 5. That reduces them to casting some weak attacks and no defensive spells, at which point it is easy to defeat them.

Eve and Norgu
These are two separate fights, but similar in style. Both will cast some hexes on you that can be pretty nasty depending on your build. They run out of energy after a while, and their casting slows considerably. You may only be able to attack or cast spells intermittently because their damage is produced primarily by hexes like Spiteful Spirit. Sometimes you'll want to finish off an opponent by attacking through Empathy or Spiteful Spirit and just taking the damage. Be careful when using spells with long cast times when fighting Eve since her interrupt skills also restore her energy.

Mhenlo
Mhenlo is a 55 Monk, so he'll only take 5 damage from normal attacks. He has a permanent Protective Spirit, so you can't just wait for it to wear off. Additionally, he uses skills which provide health regeneration, attempting to beat him via damage alone (at 5 damage per attack) is impractical. However, because his healing is produced by health regeneration, Mhenlo gets destroyed by health degeneration, lifestealing, and/or enchantment removal, so he's very easy if you have any of those. Energy denial to prevent his healing, or repeatedly interrupting Healing Breeze works too, provided that he doesn't cast Mending. It may take a while to interrupt enough of his vital skills successively, so you'll need to be able to interrupt him on demand.

Razah
Razah is a Spirit Spammer who won't move far from its spawn point, so you can't just lure it away from its spirits. Shadowsong and Wanderlust are its nastiest spirits, and can make killing it very difficult if you sit back and let it cast its spirits. An area of effect attack to kill all of the spirits can be very effective. Some builds are able to simply ignore the spirits and kill Razah before it can get very many of them up.

Melonni
Killing Melonni while she has Avatar of Dwayna up is often impractical, as it provides considerable healing and hex removal. Keep yourself alive until it wears off and then she's easy to kill.

Lukas
Lukas is purely anti-melee and thus quite easy for any non-melee class to defeat. His Riposte, Deadly Riposte, and Auspicious Parry will block many melee skills however, and can cause a lot of damage as well. Melee classes will have to strike an effective balance between attacking him and healing themselves.

Alesia
Alesia doesn't deal very much damage, but her use of Mending, Healing Breeze, and Healing Hands may force a stalemate, as she has at least 13 points in Healing Prayers. Energy denial and interrupts (especially from dazed) help greatly, though dragging out the fight until she loses her energy and then killing her will also work.

Devona
Devona brings three self-heals, so outdamaging her healing over the long run may be impractical. She won't use them until she gets to about half life, though, so you can try to finish her off by spiking her quickly and/or interrupting a couple heals. She also brings two knockdowns, which can interfere with your attempts at producing a spike, so it sometimes takes a number of tries to finish her off.

Warmaster Tydus
Tydus brings massive health degeneration and can interrupt your attempts at healing yourself. His only healing skill is Troll Unguent however, so if you can interrupt that, he dies pretty quickly.

Ghostly Hero
The Ghostly Hero is level 28, which turns out to not be terribly consequential. He'll use a bow at a distance and a sword in melee range, much like the Doppelganger. His immunity to bleeding, poison, and disease can mess up some builds, but that's the only thing that can make him much of a challenge.

Single class builds
Often when people ask how to beat the tournament, they get a reply of, take a different secondary profession and buy or capture a bunch of skills for it. That can be perfectly sensible if you wish to farm the tournament and get dozens of Bison Championship Tokens, but it is probably impractical if you only want to beat it once.

Any class is capable of beating the tournament using only skills from its primary profession. The purpose of this section is to provide builds that use skills from only one class, so they are skills that you likely already have, and should probably consider getting if you don't.

If you don't have all of the campaigns, that may make some of the skills in the builds listed unavailable to you. Some skills are easily swapped out for others (e.g., if you don't have Prophecies, replace Disciplined Stance with some other blocking stance) while others are essential to the build (e.g., the Mesmer requires Signet of Midnight).

Many of the builds listed here have been tested and they are all capable of defeating Bison if used properly. In most cases, gear isn't terribly important, provided that it's reasonable. Obviously, you want max armor, max damage weapons, perfect or near-perfect mods that are sensible for your build, and useful insignias and runes in all slots. Although not necessary, bringing several kinds of weapons (e.g. elemental, physical, vampiric, etc.) will shorten the fights. Cases in which gear does matter are expressly pointed out.

Minor Runes are generally more useful here, since you're dueling and the participant with higher maximum health may win by default. If you decide to go with Major or Superior Runes, be sure to have sufficient defense to counter the health loss.

Warrior

 * 12 Swordsmanship
 * 12 Tactics
 * 11 Strength

This build requires use of a sword.

The idea is to block most of Bison's attacks. One of the three stances should be kept up at most times. As each particular stance can only be up a minority of the time, take care not to end a stance until it was about to end on its own, anyway. Use Riposte, Deadly Riposte, and Lion's Comfort as often as available, and Bonetti's Defense rather than one of the energy-using stances as often as it is available, to recharge your energy. You do damage mainly with Riposte and Deadly Riposte, and while this build can't keep you alive forever, it can outlast Bison. Using Healing Signet against Bison takes a large risk of him hitting you and finishing you off during the cast.

Some of the enemies like to spam heals and take quite a while to wear down, but it can eventually finish off opponents like Mhenlo or Danika.

Ranger
The approach here is to keep Bison perpetually crippled, so that you can avoid getting hit. If you avoid using poison (and burning), Bison won't use purge signet, which makes him easier to kite, though these will finish him off faster. Baiting Purge Signet is easy, and if your reflexes are good, it can be interrupted. If you run around some, Bison often runs back to his spawn point while crippled before coming back to attack you, so kiting is practical. Bleeding from Hunter's/Melandru's Shot will negate his natural regeneration while you slowly wear him down.

Danika cannot be defeated, at least not easily, using this build. Most other opponents should go down quite quickly. For casters with a lot of defense like Argo, you will need to wait for their energy to run out. Casters using blind will exhaust their energy fairly quickly, and won't be able to outdamage Troll Unguent. The Ghostly Hero is immune to poison and bleeding, and will outdamage you easily if you forget to use Whirling Defense. Otherwise, he is easy to take down.

Nature's Renewal is a critical part of the build, as it really messes with the AI if you drop it behind the wall before entering the arena. The only reason this build can beat Tydus is that instead of attacking you, he mostly stands there and shoots the wall, trying to kill the spirit. Some enemies won't even bother trying to cast potentially nasty hexes, and those that do are much easier to interrupt with the doubled casting time. Gwen in particular doesn't use any skills, but just stands there wanding.

Opponents not attempted: Palawa Joko

Monk

 * 12 Smiting Prayers
 * 12 Protection Prayers
 * 11 Divine Favor

Use the knockdown-Strike chains to deal damage to Bison. Protective Spirit will keep him from dealing too much damage, and Reversal of Fortune is your healing skill. Castigation Signet is used to regain energy; use it whenever possible. Reversal of Damage can be used if energy permits, though it's best to save for when Bison is about to use an attack skill so as to reap the maximum benefits.

This build works against most other foes, though some will take a long time. Against some, you will have to spam Reversal of Fortune and wait for them to run out of Energy before you can start to deal serious damage; as otherwise they will spam heals instead of attacking, and thus you can't use Bane Signet effectively. Argo in particular takes some time to wear down.

Among the more difficult foes are Alesia (due to her healing); Warmaster Tydus (interruption, damage through degeneration); Palawa Joko; Norgu (Visions of Regret/Backfire); and Razah (Spirits). Though it is possible to beat them with patience and persistence, they take some getting used to before they can be beat reliably.

Foes which cannot be beaten except with incredible luck are Danika and Mhenlo.

Necromancer

 * 14 Blood Magic
 * 13 Curses

Sorry to use a PvE-only skill here, but without a decent direct damage skill, it simply wasn't possible to do adequate damage against some opponents. Having a reasonably high Sunspear rank (approximately rank 8) is only necessary against a couple opponents like Devona and Alesia that play for the stalemate, not the win.

You're going to get hit a lot, so you must keep Bison weakened at all times, and you'll still need massive healing. Enfeebling Touch and Blood of the Aggressor are both necessary to ensure that one is always available, as otherwise, Bison could get a few hits off right after purging weakness. Use Parasitic Bond for additional healing as energy allows and to cause Bison to use Purge Signet before weakening him at the beginning. Use Blood Renewal as often as available, and Grenth's Balance right after Blood Renewal, to fully heal yourself after the substantial sacrifice. You mainly damage Bison with Grenth's Balance.

Of those opponents not faced, only Old Mac and Danika look potentially troublesome.

Opponents not attempted: Old Mac, Danika

Mesmer

 * 14 Domination Magic
 * 12 Inspiration Magic
 * 7 Fast Casting

Keep Ignorance on Bison at all times, so that he can't purge blindness. Remember to keep him perpetually blinded with Signet of Midnight. Spirit of Failure is great energy management, as at 12 inspiration magic, it's +3 energy every time he misses, which is 92.5% of the time. Empathy is how you do damage, and use Ether Feast to heal as needed.

The only opponent that was faced and not beaten was Danika, though she may be beatable with alternate tactics. Razah is difficult, but beatable. This build handily destroys every other opponent. Potentially annoying enemy healing is blocked with either Spirit Shackles or Ignorance, depending on the opponent. Of those not fought, Gwen may prove to be a trouble.

Opponents not attempted: Gwen, Mhenlo

Elementalist

 * 14 Air Magic
 * 11 Energy Storage
 * 9 Earth Magic

The idea is to spam Blinding Surge on Bison to keep him blinded most of the time. Kinetic Armor reduces the damage you take when hit, and should be easy to cast once and keep up for the rest of the battle after that. Aura of Restoration can outheal the damage that Bison does when he occasionally lands a hit. Air Attunement and Glyph of Lesser Energy are for energy management, and should be used as often as possible.

This build should be able to overcome all opponents, even those that haven't been tried. Mhenlo takes long enough that if you draw him as an opponent, it may be quicker to just give up. Beating Mhenlo requires interrupting two consecutive casts of Healing Breeze, which can take many tries, as you must start casting Gale before he starts casting Healing Breeze in order to interrupt it.

Opponents not attempted: Danika

Assassin

 * 12 Shadow Arts
 * 12 Dagger Mastery
 * 11 Critical Strikes

Start the fight by using Smoke Powder Defense. When Bison first hits you, he'll be blinded, and immediately purge it. Be ready with Temple Strike immediately after he purges his blindness. Wait until right about when that wears off to hit him with blinding powder. If you wait long enough, he'll waste Purge Signet removing blindness right as it is about to wear off, at which point you hit him with Temple Strike again and repeat the process. If you wait too long, you'll have to use Smoke Powder Defense to re-blind him in order to get him to waste Purge Signet. Shadow refuge is your healing skill. Jagged Strike is recommended for its very quick recharge, low energy cost, and ability to do massive damage from bleeding since you can only use it infrequently due to energy constraints and the large energy cost of Temple Strike.

Most of the opponents can be beaten with this build, but Lukas can be a challenge. Time your Disrupting Stab correctly to interrupt his Healing Signet.

Opponents not attempted: Kilroy

Ritualist

 * 13 Channeling
 * 11 Communing
 * 11 Spawning Power

Start by casting Boon of Creation before the battle starts. Stand in the doorway before entering the arena and cast the four spirits in order, preceding each with Ritual Lord to shorten its recharge in case something goes wrong and you need to recast them later. You should position yourself such that when the door closes, the spirits will be inside of it--and not behind it, or it will block their attacks. Cast Painful Bond on your opponent when he comes over, and the spirits will promptly destroy him. Against Bison, wait for him to use Purge Signet once before casting Painful Bond so he doesn't immediately remove it. When you enter the arena, it's a good idea to run sideways a bit to put some space between you and the spirits. Several of your opponents may open with an AoE attack which will quickly destroy the stationary spirits.

Vampirism can replace one of the spirits if you have high Sunspear rank, or if you're missing one of the binding ritual skills. In case you find placing spirits inside the door difficult, you can bring Summon Spirits to pull the spirits through the door (you must cast after you cross the threshold but before the gate fully closes or they will remain outside).

Mhenlo, Norgu, and Razah have funky AI, so the battle proceeds a little differently, but they're quite beatable. Argo will destroy the spirits while taking minimal damage, making for a harder fight. Most opponents should be easy unless they have unusual AI, causing them to not die in the normal manner.

Dervish

 * Earth Prayers 13
 * Mysticism 9
 * Scythe Mastery 12

Keep Magni blinded by tearing down Dust Cloak on recharge. If he gets a Purge Signet off before it recharges, use Armor of Sanctity to reduce the incoming hit. Try to maintain Heart of Fury to wear him down and charge Radiant Scythe (essential for your energy) faster. If you are running low on energy use Signet of Pious Light to teardown instead of Pious Assault.

Defeating Norgu requires that you interrupt his Visions of Regret, and most opponents that play for stalemate must have at least one heal interrupted.

Unbeaten opponents: Razah, Headmaster Vhang, Mhenlo, Melonni

Opponents not attempted: Nika, Palawa Joko

Paragon

 * 14 Spear Mastery
 * 13 Motivation
 * 4 Leadership

Start by quickly charging Barbed Spear, then use it, followed by Maiming Spear to cripple Bison. You can then run around to kite him, periodically stopping to use Barbed Spear and Maiming Spear again. Use Mending Refrain if you get hit, but Maiming Spear lasts long enough that you should rarely get hit other than his initial flurry. Avoid using Stunning Strike or Blazing Spear, as these will lead him to use Purge Signet, and thus remove both bleeding and crippled. You can use Disrupting Throw for its 1/2 second activation time as a quick extra attack to charge Barbed Spear a little faster if needed.

Of all the opponents, only Razah will be troublesome if it lays down spirits of Wanderlust and Shadowsong first. Among those not fought, Danika and the Ghostly Hero look troublesome, the latter because immunity to bleeding really messes up this build.

Opponents not attempted: Kilroy, Danika, Ghostly Hero, Nika

PvE-only skill suggestions

 * Melee professions can use Sneak Attack to maintain Blindness on Magni and other physical-based opponents.
 * Ursan Blessing is capable of powering through the opponents leading up to Magni, leaving your remaining skills entirely for the last fight.
 * "You Move Like a Dwarf!" provides a maintainable cripple at even low Norn ranks, making kiting Magni significantly easier.
 * Summoned allies, such as Ebon Vanguard Assassin Support or Summon Ruby Djinn can deal damage while you focus on survival.

Other builds
This section is for the various other builds that others have posted on this page. GuildWiki can make no promises about their effectiveness, and only relabeled the headings for truth in advertising on which classes and title tracks are needed.

Assassin
A standard Critical Strike assassin will also beat many opponents, including Magni. You may have to retry should you meet Gwen or some few others, however. Put the maximum you can in Critical Strikes, Daggers at 12 and enough Shadow Arts to get some decent healing from Way of Perfection. Keep the four first effects active at all time (Critical Defenses should take care of itself as it recharges at every critical you land) and everything should be fine: Critical Defenses will stay active throughout the fight, giving a constant 75% block chance, while Way of Perfection should be able to heal whatever gets through. Be aware that Critical Strike is a sure way to both heal you and recharge your energy. Be sure to land the Horns of the Ox/Falling Spider as often as you can.
 * 15 Critical Strikes
 * 12 Dagger Mastery
 * 9 Shadow Arts

Warrior/Necromancer/Norn/Deldrimor
(Also requires a stonefist insignia on a armor piece) This build requires use of a sword.
 * 12+1+1 Swordsmanship
 * 12+1 Strength

This build uses a infinite KD lock to defeat opponents. At the start of the match, run into the ring with Enraging Charge, shouting "You Move Like a Dwarf!" as soon as you are in range (it will take a few practice tries to gauge where this point lies) in order to their interrupt their first skills, which are usually the deadliest. Use "For Great Justice!" right before making contact with the opponent, then Flail. The foe should just be getting up from "You Move Like a Dwarf!" As soon as you hit the first time, you will gain enough adrenaline to use Brawling Headbutt. Use it, and immediately follow with Dragon Slash to prime another Brawling Headbutt. (Other versions of this build recommend Steelfang Slash, but with "For Great Justice!" and Dragon Slash, this is a waste of a slot.) Repeat the combo until the match is over. Most will end in seconds. Always keep up Flail, and use Plague Touch to pass back any negative conditions. Lion's Comfort may be necessary sometimes against Magni and other difficult opponents.

Opponents not attempted: Palawa Joko

Link to where the build originated

Warrior/Necromancer/Sunspear
Works very well against melee and OK against the others though you do need to be a bit more careful and watch your timing and bars. The only opponents where this possibly fails is Mhenlo and Argo. When you get to Magni the Bison the easiest approach is to run around until the bear form wears off then turn and face him. You will be able to take him down well before he tries to re-cast.

Monk/Assassin
Against any enemy just use the chain, and they should die before using Iron Palm. For Magni, precast Reversal, and cast it once more after Holy Strike, then continue the chain and finish with Reversal. Then kite away and keep casting reversal on recharge. Rinse and repeat. Blind can give this build trouble.
 * Smiting Prayers 16
 * Deadly Arts 9
 * Dagger Mastery 9

Necromancer/Mesmer/Norn/Ebon Vanguard
Start each round with Signet of Agony and then Arcane Echo before the door even opens. The amazing power of Echoed Assassins should see you through the first six rounds, most fights taking less than ten seconds. Against Bison the most important skill is YMLAD, which will allow you to play keep away and attack with Echoed Angorodons. Grenth's Balance is there for emergencies; if you're feeling brave you can allow Bison to hit you once and then Balance him for a bunch of damage.
 * 16 Blood Magic
 * 12 Curses
 * 5 Norn Rank
 * 5 Ebon Vanguard Rank

Faintheartedness is there so melee chars don't kill off your dual assassins too quickly, and Strip Enchantment is there specifically for Alesia. The only opponents that give this build trouble are Alesia (too much healing, kills assassins quickly) and Gwen (interrupts).

You can also get it to work with 15 blood magic, 11 soul reaping and norn rank 2, and 3 ebon vanguard

you need, to cast archane echo first, then spam Ebon Vanguard Assassin Support, then use necrosis and spoil victor or grenth's balance whichever ya have acess to,

grenth's balance doesnt' work against other characters as well as spoil victor does, keep running around and spam you move like a dwarf to avoid melee situations and keep crippling him and spam necrosis when he's crippled, he can remove hexes though pretty easily, so keep crippling him, with you move like a dwarf and ya'll get him.

Necromancer/Monk
Based on the 55 monk, this build requires 55 gear.

When entering a new round, cast Mending. Approach the enemy and cast Protective Spirit. Cast Spoil Victor on foe and just wait until he/she dies. If necessary, finish foe with Necrosis. Use Healing Breeze to counter quick damage or health degeneration.

Notes:
 * Mhenlo will only die using Vampiric Gaze. One single cast of that skill should be enough.
 * Use Rend Enchantments on enemies such as dervishes or earth elementalists to make them easier to kill.
 * Razah doesn't attack so he'll only go down by spamming Necrosis.
 * Mesmers are easy, just cast Spoil Victor before they can interrupt you. They`ll go down without having to cast any other spell. Use Healing Breeze as a cover enchantment if needed.
 * For Magni, cast Parasitic Bond, wait until he removes it with Purge Signet, then cast Spoil Victor. Recast it when he uses Purge Signet again.

Mesmer/Necromancer/Norn/Ebon Vanguard/Sunspear
For most enemies, hitting the first 4 skills in a row and spamming Necrosis kills almost all of them very quickly. With Bison, start with "You Move Like a Dwarf!" to interrupt bear form, then Fetid Ground, Vile Miasma and Necrosis. His purge signet will clear the conditions but they still do a good amount of damage. Kite until the energy is back and repeat. Use Grenth's balance when he gets a few hits in to heal and do damage to him. Ignorance is good if energy permits.
 * 12 Death Magic
 * 9 Fast Casting

Elementalist/Necromancer/Sunspear
Given that you are inflicting a lot of conditions, Necrosis gives good damage every cast. Just keep him blind/weakened and apply cracked armor as often as you can. Javelin is handy for an interrupt. Of all opponents only Argo is potentially troublesome.

The inclusion of Shock or Gale is beneficial against Bison (substitute for javelin). It will give you enough time to re-blind him after purge (or can be used as an interrupt of course).

A slightly different build:

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Elementalist/Necromancer
Before you aggro, cast your Enchantments. AoR is there as a cover, and for self-heal against a random hit from Bison. This build worked against most opponents. For Danika: Wear her out a bit, and when she gets BR'd by Brutus, spike Sheena with Lightning Hammer, Lightning Orb. For Bison: Begin with Enchantments and such. Open your attack chain with Blinding Flash. He will immediately remove it, but that won't matter. Once he is in melee range, your Blinding Flash should be recharged, and thus he won't score a hit. If your Flash is recharged, count to 4 and recast. If you see him casting Purge Signet, or know it's about to come, time a Flash so he had just casted Purge Signet, and is blinded again. If he manages to score a hit, just keep casting, the wounds will heal due to AoR.

Elementalist/Monk/Norn
Cast Earth Attunement and Aura of Restoration while in the starting chamber, then Vigorous Spirit and Stoneflesh Aura while the enemy moves closer; YMLaD will interrupt their first spell, and let you drop Sandstorm on them. You can use YMLaD to keep them in the area of Sandstorm or interrupt heals - particularly valuable on Alesia / Danika / Mhenlo - and once you get to Magni, you can keep him crippled and just wear him down with Stone Daggers; he will not remove Crippled status with Purge Signet.