Note: For all map points of nameds in The Grounds (for "housegarden.txt" map files), see this quest entry.
Rend spawns in the southwestern quadrant of the zone (non-roamer just west of the ramp exit). Rend hits for a max ~9,000 and will turn invisible over the course of the fight. Note that his "Infectious Fire" effect is viral (inflicted target should move away from the group so not to spread it to other players).