Bloodlord will kill party members and ressurrect them as ghosts with increased damage. After which he'll dismount his raptor and become stronger. There are two things you need to focus on in this boss encounter. First of all: Avoid devestating slam. A brutal AoE spell which is easily avoidable. Except for that your first priority during the whole fight should be to kill the skeleton raptor EVERY time he is summoned. If you can pull that off, you'll have Bloodlord Mandokir down in no time.