Unspeakable, Unknowable

Overview
Summary
 * 1) Return to the ancient ruins of the Great Destroyer.
 * 2) Destroy Hierophant Morlog before he learns the true name of the Great Destroyer.
 * 3) Return the Tome of Rubicon to the ancient ruins. Drop it where High Priest Alkar awaits.
 * 4) Collect 4 shards of Balthazate crystal and place them near High Priest Alkar. Be sure to protect the High Priest from enemy patrols.
 * 5) See High Priest Alkar for your reward.

Obtained from
 * High Priest Alkar in Sorrow's Furnace.

Requirements
 * You must first lead High Priest Alkar to Sorrow's Furnace as part of To Sorrow's Furnace.

Reward
 * 8,000 XP

Dialogue
 * "The Stone Summit are dangerously close to uncovering the Tome of the Rubicon. Inside is the true name of the Great Destroyer, the bane of the living and nemesis of the Great Dwarf himself.  If the seals that bind that book are dispelled and the true name spoken... well, let's just say there is no worse thing that could happen in this world. I could use yer help gaining entry to Sorrow's Furnace and stopping the Summit from getting their hands on the Tome.  Will you help me?"

Intermediate dialogue 1
 * "To ensure the name was unspeakable to all but the Great Dwarf, the name was sealed within the Rubicon. There are few left with the knowledge and power to open this Tome. The day will come when the Great Dwarf and the Great Destroyer will do battle. But the time is not yet right for such a meeting. If the true name of either is spoken aloud, it would mean the end of the world as we know it. We must not allow that which is unknown to again become known. Not now. The Great Destroyer is reputed to be everything the Great Dwarf is not...evil, malicious, and greedy to the core. If that Hierophant reads the Great Destroyer's true name, he will summon upon this world the most malignant creature ever seen by mortal eyes. We must hurry. That Hierophant will not take long to dispel the enchantments protecting the Tome."

Intermediate dialogue 2
 * "We must bury the Great Destroyer's true name. The best way to do that is to consecrate the old temple and bring it down atop the Tome. Some of you should stay behind, just in case. Balthazate crystals are highly explosive. If you find enough of them, I can destroy the Temple. They're mined by an unruly lot known as the Dredge Blastrock. Kill them and collect the Balthazate they drop. This ritual will likely attract us some unwanted attention, so at least one of you should stay here with me. I won't be safe here all on my own, and if they kill me, they will get the Tome. When you find a crystal, bring it back immediately and drop it here."

After Retrieving Crystals
 * "Great Dwarf, I invoke thee. Lend me your strength."
 * "Release from the deep the power of these crystals."
 * "Bring down the walls so that we may protect the world from the evil of the Great Destroyer."

Followup:
 * None

Walkthrough
Warning: High Priest Alkar must survive! If he dies, the mission fails and the whole party is sent back to the Deldrimor War Camp.

Follow Alkar through the Furnace and watch not to lure too many groups at once. He will turn right then head down a flight of stairs and stop at the base of the stairs. He will ask that you stop Hierophant Morlog from reading the true name of the Great Destroyer. You must be ready quickly because if you are not he will rush into a swarm of Summit Taskmasters (mesmers) by himself and get killed!

Note: While attacking a group of 9 mesmers can be intimidating, the safest way to do this is to keep your healers in the back such that you are in their range but they are not in the aggro circle of the Taskmasters. Also, try and lure a few of them while he is talking to make them less intimidating. In addition, Spell Breaker works wonders, since they have no way to remove the enchantment.

Tip: If you destroy all nearby enemies, but do not kill Morlog, you can leave him and Alkar alone for some time, without Alkar dying. While somewhat risky (watch Alkar's HP and return to heal him if necessary; or just leave one monk with him), this allows you to run ahead and clear the paths to the Dredge Blastrock (who won't spawn yet) of Stone Summit dwarves. This makes the later fighting considerably easier. Also, if you head back to the earlier temple-like structure after killing a few enemies, you may see some patrols approaching. These are the same ones that would normally threaten Alkar, however since he is still battling Morlog he is not here to be attacked! Take out these small patrols and continue eliminating groups of Stone Summit. Once you have cleared them all out, then return to Morlog and kill him. This will cause the quest to update, spawning the Dredge Blastrock groups. You can now proceed as normal, but the quest will be easier since you have already taken out many enemies. This does work with an all-hench party as well: the healers will heal Alkar if you get near enough, so just run back if needed. But be careful not to let the henchmen kill Morlog before you're ready.

After defeating Morlog, Alkar will return to the base of the stairs. You should pick up the Tome of Rubicon that drops from Morlog and drop it on the square area where Alkar is standing. Alkar will now ask your party to go fetch him four Balthazate crystals so that he can destroy the ruins on top of the Tome. He will also ask that a few remain to guard him. One group will need to stay and defend him, while the other group will need to find and bring back the crystals to complete the quest. For this reason, it is difficult to finish this quest with only henchmen.

Each crystal is in the hands of a group of Dredge. Specifically, they are in the hands of the Dredge Blastrock (a boss-like mesmer). Slaying him right away will not be easy. It is important to take out the Dredge Spirit Keepers first as they are healers and revivers. It's also important to notice that sometimes the Blastrock (and other Spirit units) can revive the Keeper with Resurrection Signet! If you pull a Dredge group far enough, they might even resurrect the Hierophant, as his corpse will stay around.

If using only henchmen, pull the group of beasties with the Dredge Blastrock as far as you can; you want to get as close to the priest as possible so you can quickly return to defend him from a patrol. Attack -and kill if possible- 1 beastie in the group and immediately return to the priest to fight off a patrol. Return and kill the other members of the group and kill the Dredge Blastrock last. When the Dredge Blastrock drops the crystal, do not pick it up as this will only slow you down as you need to immediately return to the priest to defend him from a patrol. Once the patrol is dead, return to pick up the crystal. The quest is not too difficult with only henchmen, just a little more time consuming.

To do this, try to kill all group members beside the Blastrock and return to heal and possibly fight off a patrol. Then kill the Blastrock and return without the crystal if you don't have a sprint skill. Kill all non-Blastrock groups and keep returning to check on your priest. Once you fight off a group that spawns from killing the Blastrock you can pick up the crystal and take your time.

Another, slightly easier way to do the quest with henchmen is to lay 5 or 6 lines of traps on the stairs in front of High Priest Alkar. This will work well a few times, but when the traps become used, then renewing them can be a pain.

The key to completing this quest successfully is recognizing the pattern of patrols. Let us assume the party is divided into two groups, a Priest Group of two and a Crystal group comprised of six:
 * The first time the Crystal Group assaults enemies on its way to fetch a crystal shard, enemies will attack the Priest. They will be three enemies exactly, an Enslaved Ettin, a Priest of Sorrows and a Summit Dark Binder.
 * As soon as a Blastrock is slain, a larger group (containing three Summit Deep Knights) will spawn and head for the Priest. These are devastating as they knockdown the Priest so he cannot heal himself. It is imperative that the Crystal Group rush back to the Priest as soon as they have a shard. All the crystal shards are within range of sprinting back to the Priest before his defenders are overrun.

Tip: Defending Alkar can be accomplished with a single well-prepared warrior. Alkar will provide ample healing as long as the warrior stays in range. The warrior can help by bringing a few defensive stances and an AoE spell from his secondary profession. A ranger specializing in Traps is an even better choice for staying with the priest. Only the group spawning after the death of the very last crystal Blastrock will pose any troubles.

Tip: Eruption and Ward Against Melee are also very useful for defending the priest, since most of the enemies will be Warrior class.