Secondary professions for a Mesmer

Mesmer Warrior
Mesmer Warriors are most frequently seen in PvP using Illusionary Weaponry with some combination of Warrior skills (like cyclone axe). Since using Illusionary Weaponry makes the passive weapon attributes and the unique Strength attribute irrelevant from a damage standpoint, Mesmer Warriors instead look to maximize the damage done with Illusionary Weaponry. To do so, the mesmer can maximize the Illusion Magic attribute using runes, unlike a warrior primary. In addition, Flurry is a common skill, since Illusionary Weaponry's damage is unchanged by Flurry but the attack rate is increased by 33%. Mesmers can also take advantage of their superior energy regeneration to use the more energy-intensive skills within the Tactics line to mitigate damage. Finally, by using the warrior secondary along with Tactics, the mesmer is able to equip a shield effectively to provide a level of defense higher than the average mesmer caster.

Mesmer Ranger
Mesmer Ranger is a comparitively rare combination, but it can produce powerful specialized characters.

The mesmer and ranger professions each have interruption skills, and they complement each other nicely. On the downside, all ranger interrupts are bow attacks (or, in one case, a pet attack), which not only makes timing them difficult, but can also be evaded by means of stances, or ducking out of the line of sight.

Most Mesmer interrupts, on the other hand, are near-instantaneous spells and therefore can not be evaded except by means of the elite enchantments Spell Breaker, Obsidian Flesh, or Shadow Form, and some interupting signets can bypass these protections, as well. Mesmers also have a wider arsenal of "shutdown" skills than simple direct interruption. A Mesmer/Ranger can hope to combine the benefits, and avoid the shortcomings, of the interruption and shutdown skills available to either profession.

Many ranger attacks and traps inflict conditions on the target. With the Mesmer spell Epidemic, these can be spread to other enemies. Together with Fragility, and especially if there is a necromancer in the team with Virulence, the condition spreading mesmer can be a powerful spike damage player.

One of the biggest problems for a trapping ranger is the easy interruption while setting traps. The mesmer stances Mantra of Concentration and Mantra of Resolve can be used to prevent interruption. Mantra of Resolve is particularly useful because it prevents all interruptions while the stance lasts, although focused fire can quickly deplete the mesmer's energy.

Note that traps are not spells, so the mesmer attribute of Fast Casting does not speed up trapping, but Echo can be used for fast trap laying, 2 traps can be laid for every 1 trap a primary Ranger can set using this spell, this build is particularly useful for Urgoz Warren Elite Mission.

Mesmer is a difficult class to solo; though they can be effective, one of their biggest problems is the healing. Ether Feast does heal, but not effectivly enough to cover for lost health while it casts. With the Wilderness Survival skills of a Ranger, the Mesmer is able to show more resilience with healing skills and Stances. Use Troll Unguent for the healing and Dryder's Defenses for physical and elemental damage (that is almost all damage in PvE). Mesmer is already effective with Fast Casting, but the recharge duration can be solved with Serpent's Quickness. Now use Domination and Illusion (Phantom Pain/Conjure Phantasm) to inflict huge damage while staying alive yourself.

Mesmer Elementalist
The Mesmer/Elementalist can take advantage of the Mesmer's Fast Casting atribute with the Elementalist's high damage spells to create large amounts of damage until their energy is depleted. The Me/E has the potential to do the fastest simple damage dealing (that is, direct damage without relying on intricate scenarios) in the game, though without large amounts of support (Succor, Blood is Power, etc.) they are unlikely to be able to keep up their blazingly fast barrage for more than one or two kills.

Note: A popular method of fast cast spiking or fire nuking is done with stacking attunements. With the combination of elemental attunement+air/water/fire/earth attunement, energy management is effectively resolved and allows for a constant stream of fast spiking. This is sometimes used in air spike teams with 3 me/e using stacked attunements. However, this has been made somewhat less effective by the update that linked Elemental Attunement to Energy Storage

One interesting use of the Me/E is the combination of the Mesmer's energy denial skills (such as Signet of Weariness, Energy Burn, or Ether Lord with the Elementalist's "Mind" skills, such as Mind Shock, Mind Freeze, Mind Burn. The Mind skills all trigger extra damage and effects when the target has less energy than the caster. The Mesmer's energy denial skills ensure that the target has very little energy left, so that the additional effects are more likely to trigger.

Fast Casting can be used to take advantage of some of the more timing-based skills offered by the Elementalist class, as well. It is much easier to ensure that Gale hits the Ranger before they finish casting their Nature Ritual or to ensure that Aftershock connects while your opponent is still on the ground if their cast times are reduced. In addition, Mantra of Recovery provides a very effective and durable means of dealing with recharge times than simply Glyph of Renewal.

Another way to use a Me/E is with use of Fragility. Many Elementalist skills, most notably Fire ones such as Mark of Rodgort or Immolate (though there are others as well, such as Glimmering Mark), cause their target to suffer from and recover from Conditions very quickly, triggering a "strike" of Fragility both when they are hit with the Condition and when they lose the Condition. This can, when used properly, cause a very large amount of damage to accumulate over a very short time.

Mesmer Monk
Since the slow casting resurrection spells are easily interrupted, some Me/Mo bring a resurrection spell and also put attribute points into Fast Casting to allow for faster resurrecting.

Because Mesmers have many skills that affect Signets, they can dish out fast damage and support using Monk Smiting Prayers Signets. For instance, using both Mantra of Signets and Mantra of Inscriptions will allow a player to use Signet of Judgment almost 3 times more often than normal, with 12 or more points in Inspiration Magic.

Mesmer Necromancer
Mesmer Necromancer (Me/N) is a profession combination usually associated with specialization in status effects like hexes. This mix has access to a wide range of hexes from both professions, and can offsets the quick energy depletion of the Mesmer class with the option to sacrifice health using Blood Magic skills

Many of the Necromancer Curses can be combined with Mesmer Illusions to increase the effects of both spells. For example, casting Conjure Phantasm, followed by Feast of Corruption will health degenerate a target, damage all surrounding enemies, and heal the caster. Similarly, Soul Barbs compounds the damage of the numerous Mesmer hexes. Other strategies may make use of the mesmer's Fragility spell along with several Necromancer spells to cause conditions.

Another interesting benefit of the combination of Necromancer and Mesmer skills is your option to be an incredibly effective anti-caster character. Several Necromancer skills, for example Soul Leech and Mark of Subversion, can be combined with Mesmer skills, such as Backfire, to make your character an enormous thorn in the side of any enemy spellcaster. Other Necromancer skills to supplement your Mesmer anti-caster abilities include Well of the Profane, Malaise, and Spinal Shivers.

Mesmer Assassin
Daggers attack very quickly, and is a good way to do a lot of Illusionary Weaponry damage, illusionary weaponry is affected by dual strikes, but cannot use dagger chains. Assassins also have a number of hexes that can fit into a mesmer's playstyle, such as Shadow Shroud to assist spikes (particularly effective when the enemy team relies on Boon Prots for healing). Aura of Displacement and blackout could be used to "shutdown" an enemy monk from afar, While being able to safely teleport back to your group.

Mesmer Ritualist
Keep in mind that since Binding Rituals are not spells, Fast Casting does not affect them. However, both Item Spells and Weapon Spells are spells, so you can use skills like Mantra of Recovery and Arcane Echo along with Fast Casting to spam those Ritualist spells.

Because a Mesmer does not have the primary attribute Spawning Power, Me/Rt spirits will be significantly more fragile than those of a primary Ritualist.

Me/Rt can be effective using Flesh of My Flesh for in-battle resurrecting.