Thank you! Here's some Vitus fun facts~ (Spoiler warning)
He was brought onto the shelter as a criminal, meant to be used as a disposable guinea pig.
His crime was cannibalizing his friend during the apocalypse. Famine had plagued many places, and though the friend was dead, he hallucinated him to be alive and pleaded guilty to murder. The guilt ate him up so he asked for Typus to remove his emotions in exchange for being his test subject.