Kael'thas Sunstrider: Medium. Clear the instance first. Run out of his room, kill the first, 3rd, and 4th adds on one side of the instance, the 2nd add on the other side. Berserk+Thorns and aoe down the weapons, loot the mace and staff. Go to 2nd add, kill him, equip legendary staff and use it, kill 3rd and 4th adds, kill 1st when he gets there. In p4, interrupt fireballs when you can, keep staff buff up for the disorient, keep mace buff up when you can, CDs for the pyroblasts. If needed, you can run away and continuously range his fireballs to heal. At 50%, equip your normal weapon, berserk if it’s up, and chase him down with dash until he gets to his room. The last bit is the same as before; keep the staff buff up and interrupt fireballs. Keep your distance and heal during the gravity lapse. There is no pyroblast in this phase, so just use CDs whenever.