Sir Zeliekk was one of the Four Horsemen of Naxxramas. He was a paladin in life, so strong in his faith, that even in undeath the power of the Light still heeded his call, smiting his foes in battle.Though his body was forced to obey Kel'Thuzad's commands, Sir Zeliek managed to retain his sanity and morals despite his corruption. This makes him a tragic character, forced to slay what he once held dear in his heart against his will.
Cited from Wowpedia

Hope u like him, I think he's a combination of a paladin and a death knight. So I added the Light particle when he Spell.