Leonardo da Vinci

Ezio's best friend is also the series' best recruitment argument: a genius who never took the oath, never wore the hood, and mattered more than most who did. Leonardo decoded Altaïr's Codex page by page, rebuilt and doubled the hidden blade, armed Ezio with everything from a poison dart to a flying machine, and asked for nothing but the next interesting problem. Kidnapped by the Borgia and forced to build war machines, he designed every one with a flaw only he could see. The warmth between him and Ezio — teasing, loyal, decades long — is the trilogy's emotional keel.