Chiron

Chiron is a centaur in Greek mythology, (sired by Chronos in horse form)  unlike the usual frat-boy centaurs (born of a cloud that Zeus made to look like Hera, because Zeus is perpetually, like, fourteen). He's wise and kind and moderate, known for his peacefulness and as a paragon of justice. He gave us the notion of court, saying "Decide no suit, until you have heard both sides speak". 

 

He was taught the art of medicine and herbs by his foster-father Apollo, and the ways of archery he learned from Artemis. He took an arrow to the thigh ("to the knee" perhaps?), the tip of which had been dipped in the blood of the Hydra, and it will never heal, but because he is immortal it doesn't kill him. He is oracular in his knowledge, understanding astrology as well as being possessed of a wisdom so deep that he is the mentor of heroes.

 

He taught Achilles the lyre (as well as geography, javelin, and archery) and Asclepius (whom he raised) medicine. Dionysus was loved by Chiron, from whom he learned chants and dances, the bacchic rites and initiations. He taught Heracles, Ajax, Aneas, Actaeon, Theseus, Jason, Castor and Pollux, Perseus, Odysseus, and pretty much anyone else who's had an epic hymn written about him.

 

Chiron had Heracles strike a bargain with Zeus (Chiron's half brother) in which Chiron's immortality would be exchanged for Prometheus' liberation from the agony on the rock (his eternal punishment for stealing fire, which belonged to the gods, a theft I'm grateful for every time I make tea).  Zeus revered Chiron so much that he couldn't let the centaur's death be his end, and placed him as a constellation in the night sky.