So Haytham permanently crippled Achilles in the Artic Precursor site and made him give up being an assassin, which adds insult to injury that Shay betrayed him and the rest of the assassins. So what if Achilles' motivations for taking on Connor were driven by revenge? After all, what better way to get back at Haytham than to turn his own son against him and use Connor to utterly decimate the Templars? Basically, I want Dark!Achilles reveling in turning Connor against his father and using the boy to carry out his vengeance. Whether or not Connor is aware that he's being used and his reaction to finding out/realizing it is up to you.
Achilles and Connor: Connor as a Tool of Achilles' Revenge
So Haytham permanently crippled Achilles in the Artic Precursor site and made him give up being an assassin, which adds insult to injury that Shay betrayed him and the rest of the assassins. So what if Achilles' motivations for taking on Connor were driven by revenge? After all, what better way to get back at Haytham than to turn his own son against him and use Connor to utterly decimate the Templars? Basically, I want Dark!Achilles reveling in turning Connor against his father and using the boy to carry out his vengeance. Whether or not Connor is aware that he's being used and his reaction to finding out/realizing it is up to you.