Orion was a hunter in Greek mythology. There are various stories about his birth as well as the way he died.
According to the oldest version, he was the son of the god Poseidon and Euryale, daughter of King Minos of Crete. Thanks to his father, Orion had the ability to walk on water, which is how he reached the island of Chios. There, after drinking too much, he made sexual advances to Merope, the daughter of the local king. King Oenopion had him blinded and removed from the island. Blind Orion reached the island of Lemnos, which was the place where god Hephaestus had his forge. Helped by Hephaestus and his servant Cedalion, Orion reached the East where the sun god Helios restored his eyesight.
He then went to Crete and hunted with the huntress goddess Artemis and her mother Leto; he was so enthusiastic that he declared he would kill every animal in the world. Gaea, the goddess of the Earth, got angry and sent a giant scorpion which successfully killed Orion. Upon hearing the news, Artemis and Leto asked from Zeus to put their fellow hunter on the skies; Zeus agreed and turned Orion into a constellation, as well as the Scorpion that killed him.
A different version of Orion's death has it that he fell in love with Artemis; the goddess was also very much in fond of him. However, her twin brother Apollo was quite against this love affair, though, and devised a plan. One day, while Orion was swimming in a lake with his head barely visible, Apollo went to his sister and challenged her skills as an archer. To prove him wrong, he told her to shoot at Orion's head, whom Artemis barely recognised, as there was a considerable distance between them. Artemis hit the target, unknowingly killing her lover.
See Also: Poseidon, Minos, Merope, Hephaestus, Gaea, Zeus, Artemis, Leto, Apollo