Hercules is the son of Zeus, king of the gods of Olympus, and Alcmena, a mortal woman who lived about three thousand years ago. Recognizing the need for a son who would be powerful enough to defend both the Olympian gods and humanity from future dangers he foresaw, Zeus seduced Alcmena in the guise of her husband, King Amphitryon of Troezen. Thanks to Zeus' enchantment, Hercules was born with the potential for extraordinary strength, which he first displayed before he was even one year old by strangling two serpents which attacked him. As an adult, Hercules is best known for his celebrated Twelve Labors, which were performed in part to prove his worthiness for immortality to Zeus (one of these Labors, the cleansing of the Aegean Stables, was actually performed by the Eternal called the Forgotten One, who was sometimes mistaken for Hercules).
In the course of these Labors, Hercules provoked the wrath of three immortals who remain his enemies to this day. By slaughtering the man-eating Stymphalian birds, he enraged the war god Ares, to whom they were sacred. In temporarily capturing Cerberus, the three-headed hound that serves as guardian to the Olympian underworld (not to be confused with the shape-shifting giant of the same name), Hercules offended Pluto, the lord of that realm. By killing the Nemean lion, the Hydra, and other creatures spawned by the inconceivably grotesque and powerful monster Typhoeus, Hercules gained the bitter enmity of Typhon, the immortal humanoid offspring of Typhoeus and a Titaness.
However, it was the centaur Nessus who caused Hercules' mortal demise. Nessus kidnapped Hercules' wife Deianeira, whereupon Hercules shot him with an arrow. Feigning a wish to make amends, the dying centaur told Deianeira how to make a love charm from his allegedly enchanted blood, aware that it was now tainted with the lethal poison of the Hydra, in which Hercules had dipped his arrows. Some time after Nessus' death, Deianeira, distraught over her husband's latest infidelity, rubbed the supposed love charm into Hercules' shirt. When Hercules donned the shirt, the poison quickly worked and caused Hercules great pain. In an attempt to end this pain, he built a funeral pyre for himself and set it ablaze. Zeus intervened however, consuming the pyre with his thunderbolts and bringing Hercules to Olympus to be made a true immortal.