Celestan was an undetermined demigod. He never knew either of his parents. Due to this, nobody knows his last name; not even himself. He went on a quest to investigate rumors of Tartarus opening. Shortly after, however, at about the same time Atlas was freed, he joined Luke's army. Sometime after, he wound up on the shores of Ogygia, though he left for Camp Half-Blood again afterwards, knowing that he was no longer trusted by Luke's soldiers. He is almost killed by a giant, though for unknown reasons the plants healed him afterwards. Celestan then consulted the Oracle about what he should do next. After that, he witnessed the Labyrinth dying, and finds out he has been on the quest for five years, rather than what he thought was twenty days.
Celestan is tall, wears blue armor, and wields a celestial bronze sword. It has a slight axe-tip at the edge of it. He has unnatural silver hair, and red eyes.