Leonardo da Vinci helps Ezio in Assassin's Creed II by creating inventions and translating codex pages.
Leonardo is portrayed as Ezio's trusted friend during the Renaissance storyline. He studies the codex pages Ezio collects and translates their writing, helping reveal information about the Assassin order and ancient technology. Leonardo also builds or adapts devices that support Ezio, including a flying machine used during a mission in Venice.
The game draws on Leonardo's real reputation as an artist, engineer, and inventor, but it places him inside a fictional conspiracy involving Assassins and Templars. His workshop appears in several Italian locations, and his relationship with Ezio gives the historical setting a personal and practical dimension. Leonardo is not the game's protagonist; that role belongs to Ezio Auditore. Michelangelo, Raphael, and Donatello were also major Renaissance artists, but they do not fill Leonardo's recurring support role in Assassin's Creed II. The game was released in 2009.