Percy Jackson and the Olympians: Legends

Halcyon is described as a tall and gaunt old man, about sixty, with spiky gray hair, slumping shoulders, liver-spotted hands, and sad green eyes underscored with bags. He wears greenish-brown snakeskin boots and clothes made from the mighty Python that guards the Oracle. According to Luke, Halcyon might have looked handsome once, but the skin of his face now hangs loose, as if he is "partially deflated." His facial expression is so full of misery, that he looks like he's close to tears. Overall, he looks like a "very old, sickly, and fashionably dressed Einstein." Halcyon's voice is heavy with sadness, and feels alone and miserable, like a hostage.

After years of being forced to lure demigods to their doom, Hal has become a regretful man filled with sadness and regret. He apologizes to the victims he helped trap and would explain his curse to them. However after years of being forced to lead demigods to their deaths, Hal was willing to sacrifice himself to right the wrongs he was forced to commit.

After using his abilities to see into the future to save a girl’s life, he was stripped of his voice and imprisoned in his childhood home and forced to lure other half-bloods to their doom. After decades of enduring his punishment, Hal died in a failed attempt to kill the Leucrotae. While trying to foresee Thalia and Luke's future, Hal sees that Thalia will sacrifice herself for her friends, and one day find her family again. He also saw that Luke would betray his friends one day, causing Thalia to be angry with him, saying that Luke would never betray anyone. Hal gives Luke his diary, a dagger he received from the girl he had saved, and makes Luke promise not to make the mistakes he did, gifting the son of Hermes his diary from which to learn. Hal decides to sacrifice himself and lures the leucrotae into his bathroom, before setting off the Greek Fire explosion and dying, finally finding peace.