Flame Leviathan

There are two ways to start this encounter.

A) Talk to Brann directly: towers remain disabled. This is the normal mode (0 towers) whether you destroy towers or not.

B) Talk to the Keeper of Norganon: towers are activated. To deactivate a tower, you must destroy it. Leaving all towers intact is the true hard mode.

Vehicle Overview

Note: Equip all your highest iLevel items regardless of spec as vehicles are based on gear iLevels alone. The gear must be put on before entering a vehicle; its health will not change once inside. If necessary, exit and reenter.

Siege Engine Driver - Kites the Flame Leviathan and interrupts spellcasting with Electroshock.

Siege Engine Gunner - Fires down pyrite ammo from the air, kills adds and lights Tar.

Demolisher Driver - Kites the Flame Leviathan and does damage; can light the Choppers' tar on fire. Rams towers and beacons.

Demolisher Gunner - Shoots down and salvages pyrite ammo and refills the demolisher.

Chopper - Plants inflammable tar. Can pick up pyrite and drop it off to near demolishers.

As well as clearing in the area before the boss, you will want to use the Siege Engine gunner to shoot down as many of the flying crate carriers as possible to stock up your Demolishers with Pyrite barrels for the encounter itself. The encounter doesn't begin until you kill the two Collossi, so until you have cleared the trash, destroyed the Hard Mode towers you wanted to, and collected all the Pyrite you might need, don't touch those Collossi. Repair all your vehicles on the repair pad, and then head over to the clearing. There is an achievement for not using the repair pad.

When you are ready to engage the boss, get your whole raid into the formation grounds clearing past the pillars, and kill the Collossi. As soon as they die, the gates behind them will burst open and the Flame Leviathan will come forward.

The Flame Leviathan: Choppers and other vehicles should work together to drag the Leviathan through the lit-up Tar. The Flame Leviathan will target a random Siege Engine or Demolisher and chase them, switching to another Siege Engine/Demolisher every 30 seconds. Players who control these vehicles must kite the Flame Leviathan, preferably thought Tar, and everybody else should be DPSing, as there is no threat table.

Siege Engines should use Electroshock to interrupt Flame Vents.

The Demolishers need to focus fire on him the whole time.

The Choppers need to run around and every time they can, drop tar in front of the boss. Since the Tar is thrown backwards, they should drive a bit in front of the boss and throw it so it directly lands in his path.

Hard Modes

Enabling the Flame Leviathan's Hard Mode involves leaving anywhere between 1 and 4 special towers up during the gauntlet event. Leaving each tower up gives an extra 40% health and a powerful ability to the Flame Leviathan - the more towers left "alive", the deadlier the boss becomes.

Tower of Nature - Leaving this tower up gives Freya's Ward to the Flame Leviathan. Freya's Ward deals 13,500 to 16,500 Nature damage to all nearby enemies, and summons Guardians of Nature to surround the enemy. It also buffs the Leviathan with Tower of Life, which decreases fire damage taken by 10%.

Tower of Flames - Leaving this tower up gives Mimiron's Inferno to the Flame Leviathan. Mimiron's Inferno deals 150,000 Fire damage to all nearby enemies and leaves a flaming blaze behind. It also buffs the Leviathan with Tower of Flames, which increases its fire damage by 50%.

Tower of Frost - Leaving this tower up gives Hodir's Fury to the Flame Leviathan. Hodir's Fury deals 150,000 Frost damage to all nearby enemies and entombs them in ice. It also buffs the Leviathan with an additional 10% health.

Tower of Storms - Leaving this tower up gives Thorim's Hammer to the Flame Leviathan. Thorim's Hammer deals Stormstrike damage to all enemies nearby. Additional damage is taken if directly under the impact location. It also buffs the Leviathan with Tower of Storms, increasing its physical damage by 25%.