Other posts say he spawns at the top of the pyramid, but the only time I killed him he was two levels down from the top (3rd level down). He's easy to spot because he's brown. Seems to be about as hard as the other higher level named in Cazic (cenobite, named mosquito, etc.). Hits for close to 3K max. Has at least a couple hundred thousand HP. I killed all the mobs on the top 2 levels of the pyramid for a couple of hours and saw no named spawn there. Probably just unlucky.