I was toying with some flavour of very nasty quickling. I get two powers for my choices, IIRC.
Spectral quickling: Aging melee attack. Passes through walls.
Chaos quickling: Corrupting melee attack. Summons chaos quicklings.
Quickling sorceror: Casts stat drain, death ray.
Spectral quickling is basically a ghost with 1000 speed that can attack from and retreat into walls.
Chaos quickling is a massive corruption-inducing nightmare.
Quickling sorceror can fire off multiple stat drains or death rays per turn, and keep safely away from the PC while doing so.
I may change things around a bit depending on whether or not I need/want to add regeneration or punches through armor as well (which all quicklings ingame currently have).
Other ideas...
Blink tiger. Summons blink tigers. Teleports. Killing one enrages the cat lord.
Hoping to win with every class, doomed. Archer, Barbarian, Bard, Beastfighter, Druid, Elementalist, Farmer, Fighter, Monk, and ULE Priest down.