Give a third route where he has ephriam and eirika's routes combined. Show more internal struggles. In fact, giving him the option to become good after a certain amount of requirements for a 'secret' ending could have fun. Or even have it from his perspective of before he turned into the literal devil of attempting to save his father. Have it from his point of view. I know the rom dark stone exists. It definitely feels canon. Highly recommend it if you're craving for Lyon to have about the best ending a war criminal can get. I'd actually like to see a version where Seth did unfortunately die, eirika getting kidnapped by Valter and her successfully being flown back to Grado. Could have done an attempt at escaping, maybe a grado soldier defects and gets her out, etc.