@cosmos yes it's been bothering me too. a lot of things about ettsen are unexplained.
don't forget that he also now carries the item 'broken heart', that he received during the failed escape attempt. might be a clue as well. i thing that 'failed to initialize' bug might refer to the fact that he has doubts about yuriel even if his approval of her didn't reset to zero like for robia? maybe that scene with failed initialisation of his route might refer to the fact that he *could* have decided to give himself completely to yuriel but didn't because he now has his sword back and wants to rebuild his life.
but he still hates 'the princess' so maybe he wants revenge and that's why he's working with the thot now?
damn, i wish the novel was translated somewhere so i could read ahead