Michael Varus

Michael Varus was one of the praetors of the Twelfth Legion back in the 1980s and a member of the Fifth Cohort.

History
Michael was apparently ambitious and chose to pursue his ambitions, against the advice of the augur at the time, who told him the Prophecy of Seven was not for him. He led the Fifth Cohort north to Alaska where his hubris was rewarded with the massacre of the cohort by Alcyoneus. The eagle was lost, along with most of the legion's Imperial Gold weaponry. The Fifth has been regarded as "cursed" since the incident and labelled an outcast by the rest of the legion ever since.

The Son of Neptune
Michael is working for Gaea for a second chance at life. His ghost and others of his cohort attack Hazel Levesque, Frank Zhang, and Percy Jackson. However, Frank frees Thanatos and he sends the ghosts of the former legion back to the Underworld, where they are sent to the Fields of Punishment for all eternity for their treason against the gods.

The Blood of Olympus
Michael appears in Odysseus' palace as a ghost brought back by Gaea and stabs Jason Grace with an imperial gold gladius. He then is sent back to the Underworld.

Trivia

 * Varus means "crooked" in Latin.
 * Varus was the cognomen of Publius Quinctilius, a Roman Governor (and overall military commander of the province) of Germania (part of modern day Germany), who lost three legions in the battle of Teutoberg forest, one of Rome's most famous defeats; Michael Varus' name may be a play on this other unfortunate individual.
 * Michael Varus is the only mentioned Roman demi-god who was at Ithica when the heroes went there.