Metis

Metis was a daughter of Oceanus and Tethys, and the ancient Greeks considered her the personification of practical wisdom — not abstract philosophy, but the cunning intelligence needed to navigate dangerous situations. She was cleverer than any god or Titan, and it was Metis who devised the trick that saved Zeus's siblings. When Zeus needed to free the brothers and sisters Cronus had swallowed, Metis prepared the emetic potion that forced the old Titan to vomit them up. Zeus then took Metis as his first wife, and she became pregnant. But an oracle — some say from Gaia herself — warned Zeus that Metis would bear first a daughter equal to him in wisdom, and then a son who would overthrow him, just as Zeus had overthrown Cronus, and Cronus had overthrown Ouranos before that. Terrified of repeating the cycle, Zeus resorted to the same strategy his father had used: consumption. He swallowed Metis whole. But the daughter she carried was already forming. Inside Zeus, the unborn child continued to grow until one day Zeus was struck by a splitting headache so severe that Hephaestus (or Prometheus, in some versions) cracked open his skull with an axe. Out sprang Athena, fully armoured and shouting a war cry. The son foretold by the prophecy was never born. Zeus had broken the cycle — but only by absorbing cunning wisdom itself into his own body.