We had a clear room when he spawned during a single pull and aggro'd us, so I think his aggro range is room-wide. Monk was able to get himout of the room single fairly quickly.
Hits 1700 but pretty much a routine mob once slowed. No AE, no ramp, enraged and that's about it. Dropped the warrior blade.
To find fizzil's camp, go up the second spiral staircase in the center. once in the circular hallway, head out the tunnel that is STRAIGHT WEST. (green level on many maps) This is where you can find Fizzil spawn. His tunnel has 2 wanderers that can roam the entire length of the hallway. Usually spawns from the mobs on the back wall of the room.