Denis was born in 1946, to Proinsias Cassidy.
Cassidy couldn't stand being immortal and seeing his love ones grow old without him, so he abandoned Denis at an unknown point. Many years later, Denis begrudgingly let Cassidy and his friends Tulip O'Hare and Jesse Custer stay at his apartment. Denis was dying, and wanted his father to turn him into a vampire so he could live forever. Though Cassidy initially denied his request, he eventually did the deed and bit Denis.
- Denis was portrayed by Ronald Guttman.
- 11 Appearances of Denis (Preacher TV Series)
- 1 Images featuring Denis (Preacher TV Series)
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- Character Gallery: Denis (Preacher TV Series)