Grievous was a tool...of the Confederacy of Independent Systems. He was the leader of the droid army. He had bubble guts constantly, due to having a spastic colon, and most of his innards stowed in a mason jar in his rib cage.
He was well trained in the Jedi art of lightsaber battle, thanks to Count Dooku. He also had these bitchin' arms that could split in two, making it a piece of cake to wield four lightsabers. The wrists however, were limp and girly, and easily lopped off.
He wore a dashing cape, with a nice velvety inner layer. It had several pockets for lightsabers he took from slain Jedi and Starburst fruit chews. He was a little self conscience of his boney metal ass, so the cape provided some comfort.
He was once a great Kaleesh warrior, but was dicked over by San Hill of the Intergalactic Banking Clan. They blew up his ship with him in it, and put all the left over pieces in Hefty Cinch Sack and taken to Geonosis. Once there, they put his bits in the grim shell of a robot body, and called it a day.
Grievous had a terrible cough, that was said to be caused by the faulty respirator technology in his robot body. The real reason is because Mace Windu choked a bitch, and caused severe damage to his rib cage.
Grievous died when he tried to wrangle with punk-ass Obi-Wan Kenobi. Getting his ass handed to him, Kenobi took the bitch way out, and shot Grievous in his shit sack with a blaster.