Willard Decker is the son of Matthew Brand Decker and Jane Decker, and a fourth generation Starfleet officer. He was the Captain of the U.S.S. Enterprise while it was in space-dock but became Commander after the refit. James T. Kirk became Captain to confront V'ger, a sentient energy cloud destroying and assimilating the information from anything in its path, now on a path toward Earth. Decker discovered the entity was actually a sentience that had grafted onto NASA's Voyager space probe. He willingly merged with the entity, now forming a simulacrum of his beloved Ilia, to save the Enterprise and its crew. An entirely new form of life was the result.
Willard Decker was created for Star Trek II, the second television series of Star Trek that was cancelled in order to make the first film. The film was an extended episode written for the show, and at the end he and Ilia (also created for Star Trek II) would have survived. Decker and Ilia were the precursors to William Riker and Deanna Troi. A few episodes written for Decker and Ilia were updated for Riker and Troi.