For 10 points, identify this tutor of Achilles and Heracles, an unusually civilized centaur.
He was the grandfather of the musician-hero Zarex through his son Carystus, while his daughter Endeis married Aeacus and became the mother of Peleus and Telamon. This child of Cronus and Philyra married a nymph who shared her name with Tiresias's mother. He gave an ashen spear to Peleus which was later used to heal Telephus. While accompanying a hero to a feast held by Pholus, he was hit in the thigh with a poisoned arrow, but was unable to die. To end this figure's suffering, Heracles negotiated with Zeus such that this character exchanged his immortality for the freedom of Prometheus. Unlike all the beings similar to him, he was not the son of Nephele and Ixion. For 10 points, identify this tutor of Achilles and Heracles, an unusually civilized centaur.
He was the grandfather of the musician-hero Zarex through his son Carystus, while his daughter Endeis married Aeacus and became the mother of Peleus and Telamon.
Chiron [accept Cherion or Kheiron]