Richard Castillo was the helm officer of the Enterprise-C who took command after Captain Garrett's death and led the ship back to its fate.
Lieutenant Richard Castillo served on the Enterprise-C when it was thrown more than twenty years into the future in Yesterday's Enterprise. In the resulting alternate timeline, the Federation was losing a war with the Klingons, and Castillo and Tasha Yar grew close during the repairs.
When Captain Rachel Garrett was killed in a Klingon attack, Castillo took command. Knowing the ship had to return to its own time to restore history, he led the Enterprise-C back through the rift towards a hopeless battle, with Yar joining his crew. Christopher McDonald played him.