The actor plays vampire Aidan in the US remake of the hit UK paranormal drama.
"It is a darker show this time around," he told E! Online. "The first season was about them building this house and this home and trying to reconnect with their humanity.
"This season, we are all off on our individual own paths, getting really dark and naked."
Witwer also hinted that viewers will discover more about the afterlife through ghost Sally (Meaghan Rath).
"People don't know what happens in the afterlife," he teased. "We're happy to now finally reveal exactly what happens."
Former Dollhouse star Dichen Lachman and A History of Violence actor Kyle Schmid have both signed up for roles in season two of Being Human.
The show continues on Mondays at 9/8c on Syfy.
> Syfy orders season 2 of Being Human
> Being Human creator praises US remake
Watch a trailer for season two of Being Human below: