Most notorious badass in history?

[Anomalocaris]

Rasputin given how many attempts were made on his life.

fictional.  The assassin embellished the story.    In reality He was shot in the forehead from point blank range by a large caliber revolver firing an unjacketed lead bullet, and died instantly.   His autopsy report is still extant, and show he wasn’t poisoned nor beaten nor drowned.