This named has a chance to spawn after you complete the fourth step in the heroic adventure "The Descending Tower" (if the named doesn't spawn, a PH will).
He also FDs the tank. He uses Deathstrike as a proc, so it doesn't show up as a spellcast in game or in parser. I had to compare the spell landing emote to the spells text file to figure out what he was using. Jerk.
no adds on this guy but he has a "whirlwind" proc that pushes everyone back. Can direct it some (simply forces you backwards) and managed to pull him into one of the scaffolding corners to limit this, but it plays merry h377 on the mercs. Casters can avoid the effect being at max cast range.