Selin Fireheart is the first boss in Magister’s Terrace and has very little lore surrounding him. The entire fight plays similarly to Warlord Kalithresh so player’s who have ran the Steam Vaults should be somewhat familiar with the tactics required for this battle.
Drain Life: Chooses a random target and drains life from them. Can be interrupted or dispelled.
Drain Mana: Chooses a random target and drains mana from them. Can be interrupted or dispelled. This is only in heroic mode.
Fel Explosion: After Selin drains a mana crystal he will begin casting Fel Explosion until he is out of mana. It’s basically an AoE fire damage spell. Countered by destroying the crystal before he charges up too much mana.
Siphon Fel Crystal: Selin will drain mana from a fel crystal to charge up his mana bar for Fel Explosion. Simply destroy the crystal to counter this.
This fight is extremely simple and any Karazhan geared group will have little to no difficulty with it. Have everyone enter the room with Selin before you engage as he’ll block the exit once the fight starts. Have the tank grab aggro and then just begin taking him down. When he begins to drain a Fel Crystal have everyone but the tank switch their attention to the crystal he is draining and destroy it. The faster you take the crystal down then the less mana he’ll have to cast Fel Explosion. Once the crystal is destroyed he’ll begin casting Fel Explosion and you can return your focus onto him.
In Heroic Mode the fight works exactly the same, except the crystals have more life and he’ll drain mana faster. He’ll also drain mana from players (along with cast Fel Explosion) but it’ll be a very small amount.