Zenos was originally intended to be completely without redeeming qualities. The writers just backtracked on that and tried to awkwardly tack on a sob story and push him as a 'mirror' to the player character.

In itself both likely done to make up for the fact that even the outright unhinged bad guys are never really allowed to do anything truly messed up unless it affects minor, meaningless characters or other antagonists.

The solo duty in Garlemald was an excellent opportunity to have Zenos eliminate a Scion or at least severely maim them. The one sided trauma trains are wearing rather thin.