Oh and I know Klaus isn’t the bad guy anymore.

And how will they kill the most hated guy in teen wolf?

I want to choose one of the Witches, because there's so many ways Magic could be used to torment someone...

Klaus would do something (gloriously) terrible...

Dahlia would do something (traditionally) terrible...

Inadu would do something (horrifyingly) terrible...

Cade would drag him to hell and do terrible things...

Silas would either mind-rape him (as an immortal), or torture him extensively via Magic (as a Witch)...

And Kai either wouldn't care, or he'd propose some sort of alliance, gain Gerard and his allies' trust and stab them in the back in some sort of twisted (but extremely cathartic) and hilarious manner when all of their plans have come to a climax for sweet, sadistic and (probably) ironic lols...