you converted it earlier? why didn't ya say so?

linky? and i think Outsider is the way to go, as the resemblance to xorn is likely more than superficial!
for comparison, some preliminary stats for the abomination of Diirinka:
Abomination of Diirinka
Large Outsider (Extraplanar)
Hit Dice: 20d8+X (X hp)
Initiative: +X
Speed: 20 ft (4 squares), burrow 20 ft (4 squares)
Armor Class: 23+ (-1 size, +X Dex, +X natural), touch X, flat-footed X
Base Attack/Grapple: +20/+X
Attack: X
Full Attack: 3 claws +X melee (2d4+X) and 3 bites +X melee (1d3+X)
Space/Reach: 10 ft/10 ft
Special Attacks: attach, energy drain, rend 2d4+X
Special Qualities: all-around vision, damage reduction X/bludgeoning, darkvision 60 ft, earth glide, fast healing 3+, immunity to acid, cold, electricity, fire, and poison, spell resistance X, spell turning, tremorsense 60 ft
Saves: Fort +X, Ref +X, Will +X
Abilities: Str X, Dex X, Con X, Int X, Wis X, Cha X
Skills: Hide, Move Silently
Feats:
Environment: Infinite Layers of the Abyss
Organization: Solitary
Challenge Rating:
Treasure: None
Alignment: Chaotic evil
Advancement: ---
Level Adjustment: ---