Freed from Crank-a-kai: "Are you SURE I'm free? And you seem to want to be friends, but...I dunno."
Contrarioni is based on the amanojaku (which is also its Japanese name); a small oni-like demon that instigates humans to act upon their darkest compulsions and turn to evil, and will always lie or state the opposite when interrogated. The name is used in common language to mean "contrarian, backwards, someone who just can't be honest with themselves".
Contrarioni is a portmanteau of contrary and oni.
"Onimich" is a pun on oni and the phrase ohne mich (without me).