Abyssal Rotfiend
Large elemental humanoid (demon, undead)
Level 26 Controller XP 9000

Initiative +20        Senses Perception +20; truesight 20
Abyssal Fields aura 5; each enemy within the aura cannot teleport.
HP 245; Bloodied 122
AC 40; Fortitude 38, Reflex 36, Will 40
Immune fear; Resist 20 fire, 10 necrotic, 20 variable (3/encounter)
Speed 6, fly 6 (hover)

Skullsplitter (standard, at-will) Psychic

Reach 2; +28 vs Reflex; 3d8+8 psychic damage, or 2d8 + 8 psychic damage against a bloodied target.

Conjure Abscess (standard, at-will) Psychic

Ranged 10; +29 vs Fortitude; 2d8+8 psychic damage, and if the target moves more than 2 squares on its turn, it takes 2d8 extra damage (save ends). If the abyssal rotfiend is bloodied, the target takes the damage for moving 1 or more squares.

Floating Despair (standard, encounter) Psychic, Zone

Area burst 2 within 10; the burst creates a zone of dark miasma that lasts until the end of the abyssal rotfiend’s next turn. Any enemy that starts its turn within the zone takes 10 psychic damage and grants combat advantage to the rotfiend until the end of its next turn. Sustain Minor: The zone persists, and the rotfiend can move it 5 squares

Alignment Chaotic evil        Languages Abyssal, Common
Str 26 (+21)      Dex 25 (+20)      Wis 25 (+20)
Con 29 (+22)      Int 20 (+18)      Cha 32 (+24)

Published in Monster Manual 2, page(s) 52, E3 Prince of Undeath, page(s) 4.