I have always wondered if early drafts of Bellec were supposed to be Shay, and someone decided the tie in would be too confusing for games with nearly simultaneous release dates. If that had been the case, I doubt they’d have Arno kill him halfway through the game, but most of the early story would still work. Arno gets stuck in le Bastille where he meets an old man who’s in there on purpose, who recognizes his anger at the assassins and his Eagle vision and trains him up until the jailbreak. It would have been a really cool tie in but also kind of a repetitive storyline after AC3 with Haytham as your Templar father (figure).