Prince Kael’thas may be found at the Magister’s Terrace, a 5-man dungeon. There are a few tips to take in mind during this encounter. It is a DPS race as much as a survival race. Stay alive and you win. The video below shows a Kael kill within 3 minutes. Kael’s spells can be interrupted and reflected. No aggro list, no melee attacks. He will spam fireball often.
Thirty-seconds after engaging Kael, he will summon a single Phoenix. Its hellfire deals 1400 damage. Your group must avoid it at all times. At 50% Kael’thas will channel Gravity Lapse causing 400 damage. However, with a twist. Your speed floating or swimming is increased a lot. Maneuver down just ten feet above the ground, and avoid the three arcane spheres. These spheres resemble the ones from Mogrim Tidewalker, just they float around on the air. Swim away from them. The arcane spheres deal 2800 Arcane damage.
Once Gravity Lapse is over, and you fall to the ground, beat Kael with everything you got. He would be roughly under 20% health by now. Video by 0daNobunaga.
Below are short clips of each boss in the Magister’s Terrace 5-Man dungeon – by eventhorizzon: