Kingdom of Knuffel

I love Voltaire's music. Some of my favorite songs of his are 'When you're evil', 'Goodnight Demon Slayer', 'Stuck with you', and 'The Night'.

Also if you've seen The Grim Adventures of Billy and Mandy, he did the song for the evil alien meteor that eats brains.

What are some similar artists/groups that I could get into?

Ah, maybe take a look at the "similar artists" page at last.fm (https://www.last.fm/music/Voltaire/+similar)
I love Voltaire too haha. The only slightly similar thing I listen to though would be Gogol Bordello and Emilie Autumn? Nothing with his sense of humor though