Amdor

You're welcome, although it's possible someone just pops up and tells me I'm completely wrong (I'm rather new after all).

Yes, you could cast December's Curse if you're within 12" of Killjoy and it would randomize since it's a . If you hit the gamin, you would flipping to hit normally (unless I'm mistaken) and if Raspy's attack wins the gamin's defence by at least 6 (easy to cheat if jokers aren't involved) you can cheat the damage to severe and get a total of 6 damage on Killjoy (4 from blast and 2 from Explosive demise).

Or Paralyse and then Devour him

Sadly that won't work. Devour only targets living models and Killjoy is an undead.

Confirmed, it's Misaki Mei from the anime Another (or actually her doll likeness)