>>34978297Dark/Fairy
I'd probably have it be based on an imp, since they're part of folklore, and would fit well with the dark/evil type since they're described as being pranksters. It could be a single stage pokemon; or, a two stage where the first is an imp, and the second could be something like the red and blue oni (the colors could be based on gender, or by shiny). For the sake of the stats, I'll assume its either one stage, or the second stage of the two stage evolution.
Abilities: Prankster, Frisk
Hidden Ability: Infiltrator
Total: 550
HP: 65
Atk: 126
Def: 70
SpA: 102
SpD: 70
Spe: 117
It's moveset would be mostly offensive, adding some new physical fairy type attacks. It could also have some fire type moves since imps are said to have the ability to conjure fire. I'd also give it a couple status moves to pair with prankster.