The BD hero could be in Project E, depending on when it is set (mages may live hundreds of years, and Seth was still around, in fighting shape, after about a hundred years). The only problem making the BD hero a playable character would be that he couldn't defeat Damian if the game was set before DKS, and afterwards the Divine One and dragon knight would be more likely protagonists. As an NPC, Larian would have to assume a gender and appearance, though it would be easy to mention visiting an illusionist to explain a change from the BD character.
