Male/NB Arcanoloth Planar
12+24 Hit Dice
Location: The Friendly Fiend
Intelligence: Supra-Genius (19)
Armor Class: -8
Movement: 12, Fl 18 (B)
Hit Points: 92
Number of Attacks: 3
Claws (x2): d4, d4
Animate Dead (per spell, Yugoloth Ability)
Advanced Illusion (per spell, Arcanoloth Ability), 1/day
Cause Disease (per spell, reverse of Cure Disease, Yugoloth Ability)
Charm Person (per spell, Yugoloth Ability)
Continual Darkness (per spell, Arcanoloth Ability)
Control Temperature, 10' Radius (per spell, Arcanoloth Ability)
Fear (per spell, Arcanoloth Ability), 1/day
Gate, per spell: 1-6 Mezzoloths, d2 Dergholoths or 1 Arcanoloth (40% chance), 1/day
Heat Metal (per spell, Arcanoloth Ability)
Improved Phantasmal Force (per spell, Yugoloth Ability)
Magic Missile (per spell, Arcanoloth Ability)
Poison (Arcanoloth Ability): Each successful Claw hit imposes a cumulative -1 penalty to attack rolls on target. Bless, Neutralize Poison or Slow Poison can remove this, but otherwise effects are permanent.
Produce Flame (per spell, Yugoloth Ability)
Warp Wood (per spell, Arcanoloth Ability)
Immune to Acid, Fire (including Magical, Dragon) and Poison
Immune to Mind Altering spells (Arcanoloth Ability), and all 1st Level Illusions
Invisibility (per spell, Arcanoloth Ability)
Takes half damage from Gas
Regenerate 1 hit point per round
+3 or better Weapons to hit, but takes full damage from Silver Weapons.
Alter Self (per spell, Yugoloth Ability)
A'Kin can read and write all known languages.
Fly (per spell, unlimited duration, Arcanoloth Ability)
Shape Change (per spell, Arcanoloth Ability), to any humanoid form.
Spell-casting ability as 12th Level Mage, (Arcanoloth Ability: 4/4/4/4/4/1)
Telekinesis (per spell, Arcanoloth Ability)
Teleport Without Error (per spell, Yugoloth Ability)
Takes Double Damage from Cold
Takes full damage damage from Silver Weapons
Magic Resistance: 60%
Size: M (6' feet tall)
Morale: Champion (16)
XP Value: 20,000
Special Equipment: Cube of Force, Ring of Spell Turning
Note: All Spell like abilities are usable once per round unless otherwise noted. He also has a Sword of the Planes (that he probably swindled from one of Shemeska's people) that he's willing to sell to the PC's during the Harbinger House adventure.
Source: 2nd Edition AD&D 2624, Uncaged: Faces of Sigil, pages 8-9
Ed's Notes: If you need help role-playing him, think of an evil Varys or to a lesser extent, Littlefinger from Game of Thrones. That's his role in Sigil: Spoil everything for everyone, without anyone knowing it was him, and keep making himself indispensable to everyone. He will really only ever be an adversary to the PC's if they get involved in some high-up Faction politics or are planning a coup against The Lady that has a chance of success. Otherwise, the worst he'll do is use them in some way that actually benefits them in the short-run, but might makes them some powerful enemies.