Young Devils
i dunno
doesn't really have a flow to it

Young Devils

Youth Demons?

Juvenile Fiends?

The Mischievous Eleven (The [Adjective] [number] technique)

League of Super Evil (hahahahahahaha)

Operation Detonation

The Innocent Ones?
^^that's funny right there

Murder of Crows?

Whatever it is, we need a calling card.
obviously we need a calling card

my character could spraypaint something or other on a wall

i don't want our calling card to be some dead guy hanging upside down from the ceiling or something demented like that