Like the most-celebrated rock stars, the most famous mathematicians live fast and die young. Evariste Galois was 20 when he went to meet the Supreme Fascist, on the wrong end of a bullet in a duel. It's not clear who his opponent was.
He's held up as a romantic hero: the story goes that the duel was over a young lady of his acquaintance, and that he spent the night before his death writing down all of his crazy-brilliant mathematical ideas interspersed with love letters - meaning that he was too exhausted to shoot straight at dawn.
The truth isn't quite so clear-cut - he did write letters on the eve of his duel, but largely fragments of what he was working on (Galois, throughout his short career, was criticised for unclear explanations). However, he did invent group theory, which is one of the cornerstones of modern maths.
Galois's works could have been much more extensive had he not kept getting himself thrown in prison for seditious activities. A staunch republican1, he was finally banged for illegally wearing a uniform on a march - less than a month after his release, he was dead. He'd been kicked out of university for complaining that students had been locked in to prevent them marching, and had up for drinking a toast to the king while holding a knife - a clear threat to the monarch's life.
With such a farcical life executed so incompetently - and with such brilliant maths flying around in the background, it's hard to argue that Galois could be anything other than a mathematical ninja, and I welcome him to the ranks.