Juan

The holder of the Fi the Charm of Time

Unity Storyline
Sometime in 2017-2018 Juan met Connor and Stephen at a nearby island.

Later on in the Story he aquired Fi, the Charm of Time and used it to travel back in time in an attempt to stop Arthur

Chapter 8
Juan is mentioned by Arthur when he says "Took this from your friend" refering to Fi.

Juan's Fate
Arthur later on reveals that he did in fact take it off of Juan's body, not specifying if he infact killed Juan.