What is the name of the Assassin mentor who trains Arno in Assassin's Creed Unity?

In Assassin's Creed Unity, Arno's Assassin mentor is Pierre Bellec.

Bellec is a veteran Assassin who encounters Arno during the French Revolution and helps guide his entry into the Brotherhood. He trains Arno in Assassin methods and serves as an experienced, disciplined figure within the Parisian order. His relationship with Arno becomes important as the story examines loyalty, doctrine, and disagreement inside the Brotherhood.

William Miles is a modern-day Assassin leader and the father of Desmond Miles. Shaun Hastings is a modern-day Assassin historian and analyst. Al Mualim is the mentor and leader associated with Altaïr's story in the first Assassin's Creed. None of those characters is Arno's mentor in Unity.

Unity was released in 2014 and is set mainly in Paris during the French Revolution. Bellec's role is separate from that of Elise de la Serre, Arno's childhood friend and a Templar. Their connection creates one of the game's central conflicts between personal loyalty and the Assassin-Templar struggle.