Hank Terrill is the cousin of Raymond Terrill, the contemporary Ray. Apparently, Hank grew up hearing stories about his cousin, "the Night Boy", who had a fatal allergy to sunlight. Hank did not entirely believe these stories, however, and so after the man believed to be Ray's father died, Hank went to Ray's house in Philadelphia to share his ideas. He coaxed his cousin out of the house, and so exposure to solar radiation activated Raymond's powers.
Even beyond the original six issue limited series from creative team Jack C. Harris and Joe Quesada, Hank acts as a significant supporting character for the Ray. In the original limited series, a "light entity" apparently created during the Big Bang which formed the Milky Way galaxy threatens to return to the Earth. Due to the mental instability of Dr. Polaris, the Ray is thrown back/forward into the entity's path and inadvertently leads him back towards Earth. Hank is sent by Caldwell the Candle Man, and an amalgam of Dr. Polaris and the original Ray into Raymond Terrill's mind. Hank saves the world by convincing Ray to "shut the door" on the entity.
Hank is characterized as more worldly than his cousin. He is also a smoker.