Leonardo da Vinci

Leonardo Da Vinci (April 15, 1452 – May 2, 1519) was an Italian polymath, scientist, mathematician, engineer, inventor, anatomist, painter, sculptor, architect, botanist, musician and writer of the Renaissance.

Assassin's Creed II
Leonardo Da Vinci is a close and the best friend of Ezio (he will become his friend in the game). He will be his personal engineer like Q in James Bond, making him various inventions (gadgets, items and weapons). He's the creator of the Hidden Gun, the Smoke Bomb, the Flying Machine, the dual Hidden Blades... According to Patrice Desilets (creative director of the game), Da Vinci allows Ezio not to cut his finger unlike Altaïr by adjusting the Hidden Blade.