Heracles

Heracles is a son of Zeus and the mortal Alcmene, and Hera hated him from birth for it. His name means 'glory of Hera', which is either an attempt to appease her or a joke at his expense; she sent serpents into his cradle, and he strangled them.

The labours are a penance, not a career. Hera struck him with madness and in it he killed his own wife and children. The Oracle at Delphi sent him to serve his cousin Eurystheus for ten labours as expiation, and Eurystheus disqualified two on technicalities — the Hydra because Iolaus helped, the stables because he took payment — so ten became twelve.

They escalate from beasts to the impossible: the Nemean Lion, the Hydra, the Erymanthian Boar, the Augean stables, the Cretan Bull, the belt of the Amazon queen, the cattle of Geryon, the apples of the Hesperides, and finally Cerberus, hauled out of the Underworld and handed back.

His death comes from the Hydra, years later. His wife Deianira, deceived into thinking it a love charm, smeared his tunic with the blood of a centaur he had shot with a Hydra-poisoned arrow. The poison could not be removed. He built his own pyre, and Zeus took what was immortal in him up to Olympus, where he was finally reconciled with Hera.

He is also the only Greek hero who ends up a god. Most heroic careers close in the Underworld like everyone else's, but Heracles is divided at death — the mortal part burns on the pyre, the immortal part ascends — and Homer's Odysseus reports seeing his shade in the Underworld while the man himself feasts on Olympus. Even the sources found that difficult.