Ten

The Illidari Council is a group of four blood elf bosses in the Black Temple. The fight is comparable to High King Maulgar since it sports a difficult pull and a rather chaotic battle for survival, which requires high situational awareness and fast reflexes from all raid members.

Abilities

All four bosses share a common health pool of initially 4,300,000 HP. Damage done to any boss is deducted from this pool, they automatically all die when the pool is depleted. The enrage timer is 15 minutes.

Lady Malande

Empowered Smite: 2 sec cast, 5,463 to 6,037 holy damage, not reflectable
Divine Wrath: random target, 5k initial holy damage plus 8 second DoT for 2,5k fire damage per tick
Reflective Shield: 20 sec self shield, absorbs up to 25k physical and/or magical damage, half the absorbed damage is reflected to the attacker, does not protect against physical interrupts (like kick or pummel)
Circle of Healing: 2.5 sec cast, fills the common health pool for 100k, 20 sec CD, interruptible

High Nethermancer Zerevor

Arcane Bolt: 2 sec cast, ~15 k Arcane Damage, interruptible
Flamestrike: 10 yard fire AoE, random location, 5k initial damage plus 3k per tick over 12 seconds
Blizzard: 10 yard frost AoE, random location, 6k frost damage per tick over 12 seconds
Dampen Magic: self buff which reduces magic damage taken by 75% and healing taken by 500
Arcane Explosion: 10 yard AoE cantered around him for 9k Arcane Damage, used only if any target is within 10 yards, resistible

Gathios the Shatterer

Melee: cannot crush
Hammer of Justice: Stuns a random target within 10-40 yards for 6 seconds
Consecration: 21 seconds 10 yard AoE around Gathios for 2,250 every 3 seconds, 30 sec cooldown
Seal of Command: 30 sec self buff increasing melee damage dealt by 70% (holy), shared CD with Seal of Blood
Seal of Blood: 30 sec self buff for +800 holy melee damage, shared CD with Seal of Command
Judgement: Both seals can be judged (Command for 7k holy damage, Blood for 11k holy damage over 9 sec), Judging Command can be spell reflected, Judging Blood cannot
Blessing of Spell Warding: 15 sec buff granting immunity to magic damage, cast on one of the other bosses (usually Malande), shared CD with Blessing of Protection
Blessing of Protection: 15 sec buff granting immunity to physical damage, cast on one of the other bosses (usually Malande), shared CD with Blessing of Spell Warding
Chromatic Resistance Aura: 30 sec buff on all three other bosses, increasing their resistance to all by 250, 1 min CD shared with Devotion Aura[Please confirm: I think this is wrong. As far as I can tell it works like a pally aura, that is it applies to "all party members in range", including Gathios himself. The range is finite and does not affect Zerevor in standard positioning. Devotion Aura is the same.]
Devotion Aura: 30 sec buff on all three other bosses, increasing their armor by 20%, 1 minute CD shared with Chromatic Resistance Aura

Veras Darkshadow

Deadly Poison: debuff for 1000 Nature damage per second over 4 sec, cannot be removed
Envenom: attack on a Deadly Poisoned target, removes the debuff and deals ~6k poison damage
Vanish: Same as the rogue ability Vanish, 30 sec duration