Basics

Enrage - 10 minutes - Lots of DPS required on this one!
Damage output: Main Hand Melee - 3,500
Off Hand Melee - 1,500

Raid Setup:

7/8 Healers.. probably 7 as DPS is needed.
1 or 2 Tanks: There is no MT, its just whoever picks up the aggro after whirlwind. 1 Warlock Tank for Demon Phase with about 300 Fire Resist.
Lots of DPS as its a tight squeeze to beat the enrage timer.

A Limited Invulerability Potion can also come in handy to everyone in dealing with the Phase 1 ability Whirlwind: it removes the Rend and saves the healers some healing aggro. Not sure if this is still the case, need to confirm.

Abilities in Human Form:

Whirlwind
Leotheras will start running around Whirlwinding, like Warchief Kargath Bladefist from Shattered Halls or Sartura from AQ40.

The Whirlwind does 3,000 physical damage to anyone it hits, and also applies a non-dispellable DoT called Rend, that deals 2,500 physical damage every 3 seconds, which is removable by Divine Shield, Blessing Of Protection, Limited Invulnerability Potion and Ice Block. This lasts about 12 seconds.
He will do another Whirlwind 20 seconds after the first one ends.

He will reset his aggro after every Whirlwind.

Leotheras should not be attacked by anyone except the tanks when the Whirlwind is about to end..say 4secs before. NO DOTS FOR WHEN HE RESETS
This is where pally tanks come in handy

Abilities in Demon Form:

Chaos Blast.
A bolt that does about 100-200 Fire damage to the target and everyone in a 8 yard range of the target. This base damage is insignificant, however it also gives a debuff that increase fire damage taken by 1,675, and this debuff stacks without limit. This ability does not critically hit.

Inner Demon

Summons an Inner Demon of a few random people. Each Inner Demon can be attacked only by the person it spawned from. If you do not kill your Inner Demon before Leotheras gets back into humanoid form you will become Mind Controlled for 10 minutes and can't get out of it. The demons hit for roughly 1,000 on mail and shoot out Shadow Bolts dealing around 2,500. This ability will not be cast on the current tank, be it the MT or the warlock offtank.

Note that your Inner Demon, if you have one, will be rendered normally, whereas the Inner Demons of other players will appear as black silhouettes.

Phase 0

Kill the three channelers keeping him banished.
Spread them out and focus fire them down one by one.

Phase 1

On Leo himself...
About 15 seconds into the fight he will start to Whirlwind around for about 10 seconds. You need to be spread out and keep moving away from him to avoid getting hit. The tank needs to follow him around and grab him as soon as he's out of the Whirlwind and accumulate aggro. Nobody attacks him for at least 5-6 seconds after he's stopped so the tank can hold aggro. 15 seconds after he's stopped the first Whirlwind he'll do another Whirlwind. He will turn into his Demon Form while he's doing his second Whirlwind.

Phase 2: Demon Phase: 60 seconds.

Leotharas turns into a demon and remains stationary while shooting out Chaos Blasts on his target. In this phase, the warlock offtank tanks Leotheras from range so that melee DPS can still attack him without being hit by Chaos Blast.

It doesn't really matter where the warlock stands as long as there it is clear of Leotheras and there isn't anyone in a 10-15 yard range of him. Everyone needs to be well clear of the offtank warlock to avoid being hit by Chaos Blast, which Leotheras will start casting on the warlock.

15 seconds into the phase, he'll summmon Inner Demons for some random people, and they will have to kill their own Inner Demon (like that boss in ZG). After the 60 seconds are over, he'll go back into his humanoid form. Healers where some damage gear?.

Phase 3: Split into both forms at 15%

His demonoid form will split from his humanoid form, leaving you with 2 bosses to fight.

His demon form needs to be tanked again by the offtank warlock, with nobody in a 15 yeard range of the warlock. His demon form will be the same as in Phase 2, except he won't do Inner Demon anymore.

His humanoid form needs to be tanked by the main tank warrior again and it will act the same way as in Phase 1, opening with a Whirlwind and repeating it every 15 seconds just like in Phase 1. You need to nuke down his humanoid form as fast as you can, as he will be near his enrage point now. As soon as his humanoid form dies, the fight is over and the demon form vanishes.

EG Video:

http://files.filefront.com/EG_vs_Leotheras_the_Blindavi/;7506018;/filein...

Placement:
http://vigilantes.zind.net/files/Leotharas-the-Blind-Positon.jpg

Discussion thread: http://vigilantes.zind.net/node/4038