Boss Focus: Shade of Aran
In a Nutshell
The Shade of Aran is an optional encounter on your way to the top of the tower. He controls most of the respawn in the library, however and should be dealt with if you are in risk of wiping on the content after him.
The fight itself is very unique and fun. As a healer you need good reflexes and situational awareness in order to stay and keep other people alive.
Rundown
The fight starts as soon as someone enters Aran’s room far enough to proximity aggro him. This player will be the target of Aran’s first spell. From then on, he is not tankable and will pick his target randomly.
He will almost exclusively cast spells to deal damage. He knows 3 basic damage dealing spells: Fireball, Frostbolt and Arcane Missiles. One from each school of magic known to mages. He can, and should be, interrupted. This will lock his ability to use spells from that school for a short duration. Only if all three schools are locked away simultaneously he will enter melee combat and start running around. This should be avoided however, since he possesses a very nasty AE Counterspell centered on him. If he starts running around, you will suddenly be in range while casting a spell, resulting in you spell being countered and your holy school being locked down for 10 seconds. Ouch!
On a side note, he also casts Chains of Ice once in a while. Not very threatening at all, but it may be recommended to remove them, depending on the situation. If a melee is caught out of range of Aran, or a Blizzard is going round, I would advice to remove the debuff as soon as possible.
Besides these basic damaging spells, he also has 3 special spells that he will cast in regular intervals. Those cannot be interrupted, but can be avoided if you stay alert.
His Arcane Explosion is one of them. As a healer, this spell offers you a moment of respite. Aran will first teleport himself to the center of the room, pull everyone to him, cast a slow effect on everyone and will then start to cast the Arcane Explosion. The casting time is 10 seconds, this gives everyone ample time to reach the safety zones between the pillars surrounding the room. If anyone messes up or is generally slow to react, you can help them by removing their slowing debuff with Dispel Magic.
Another of his special casts is the Blizzard. Unlike the normal version this one is not stationary but moves around the room in a circular fashion, clockwise. You will get a warning beforehand, a single icicle will drop from the roof a few seconds before the Blizzard will start. This will give you some time to reposition yourself to avoid the damage done by this spell. If you are unlucky and get caught inside of it, don’t try to outrun it. Either walk through it, or try to run through Aran in the center of the room. As long as you don’t cast non-instant spells you are safe. 
Next up is the most critical of his special abilities: Flame Wreath. This spell will last for 15 seconds or so and will surround 3 players with a circle of flame. Any player that moves, turns or jumps while inside this circle (or touching) it, will trigger it. When triggered, it will deal a nice chunk of fire damage, around 5k I think, and will knock nearby players into the air and around the room. If you are lucky you can survive this, but if anyone lands near another player affected by Flame Wreath, you will get a lovely chain reaction that will wipe your raid swiftly.
Aside from those special attacks, he also possesses two triggered spells:
As soon as his health points reach the 40% mark, he will summon 4 Water Elementals to aid him. They will “only” last for 90 seconds and follow normal aggro rules. If no one targets them, they will go for the healers first. It’s important to deal with them quickly since they put a considerable stress on the healers. If you have warlocks with you, you can go easy mode and Banish and chain-fear the elementals. If not, you have to kill them as quickly as possible. If you are able to get near an elemental pop a Psychic Scream to get rid of it for a while.
The second trigger is optional. If your dps is good, you will not encounter it. As soon as his mana drops below the 20% mark, he will mass polymorph the entire raid and will sit down to drink. A few seconds later he will stand up and start to cast a super pyroblast. Dealing 5k damage or so to every raid member. This is the perfect time to chuck a healing potion or use your Healthstone. You will be very vulnerable right after the pyroblast. Be ready to shield and heal his first target afterwards.
Watch out for
A lot.
- During a Blizzard, stay mobile. Don’t let yourself be caught in it. If it happens anyway, run through the middle using Prayer of Mending, Renew and Power Word: Shield while on the run.
- As soon as the Water Elements spawn, Fade. It helps to avoid their attacks for a while. If your dps is quick to react, it will spare you completely.
- Don’t let anyone drop too low on health if you can help it. Aran has a tendency to target people whose health total is low, finishing them off if unattended. So try to keep everyone topped of as much as possible.
Healing Roles
There are no tanks and Aran will pick his targets randomly. So just heal what you can as quickly as you can. This is a fight where Flash Heal really shines. 
Rewards
If you survive the madness that is Aran, you can get some very nice loot from the old man. Aran’s Soothing Sapphire is a very nice offhand and your feet may be happy to get to know the Boots of the Incorrupt.
