The writer told SFX that the BBC Three show's latest six-part run will climax with an ending that "will leave you guessing".
"There will be much discussion about the end," Whithouse hinted.
The finale will also contain "cameos from two guests" who featured in Being Human's fourth series, but Whithouse ruled out return appearances from any of the show's former cast, including Aidan Turner, Russell Tovey and Sinead Keenan.
"Mitchell [Turner] isn't coming back, because he's dead. And so are George and Nina!" he insisted.
The new series of Being Human stars Damien Molony, Michael Socha and Kate Bracken and will also feature Whitechapel's Phil Davis as the villainous Captain Hatch.
> Being Human: Why we're excited for Series Five
> Being Human creator for new BBC One spy drama
Watch a trailer for BBC Three's 2013 schedule - including Being Human - below: