King Vega is the main antagonist of the anime Ufo Robot Grendizer.
King Vega was the ruthless ruler of planet Vega. When his world became unstable due to the exploiting of the radioactive material named Vegatron, he began an expansionist campaign of conquest to find a new place to live.
His first targets were the neighbour worlds to Vega. One of them was Fleed. He approached King Fleed with apparently benevolent intentions, and the King did not suspect anything, and he even got his son Duke engaged with Rubina, King Vega's daughter. But as soon as they felt confident, he turned against them, attacking Fleed with a huge fleet of war ships and gigantic robots, decimating their armies and bombarding their cities with Vegatron bombs. The Royal Family was murdered and soon they took over the planet.
However, their own Vegatron bombs turned the idyllic planet they intended colonize on a radioactive wasteland, and they were unable to fulfil another of his targets: seize Grendizer, an Humongous Mechawas the embodiment of the Fleedian god of war. Duke, Fleed Crown Prince ran away with Grendizer before they got their hands on it.
A while later his army struck Earth. During its first raid they learnt Duke had found shelter in that planet along Grendizer. For a long while, King Vega remained on his planet, leaving the war against Grendizer to his commanders. However, in the last part of the series, Vega homeworld finally died, and he moved with his army to Skul Moon Base -the Vegan Space Base on the dark side of the Moon- and personally oversaw the war against Grendizer. However, after Gandal's death, he led the final offensive against Earth.