I think episode 14 is still my favorite episode of him so far. I mean, he's great in every single one of his scenes and nails every single one of them, but the scene of him walking toward XY's room after finding out her real identity, while remembering every single cruel thing he's inflicted on her while she saved his life multiple times, even going as far as using her body as a shield in order to protect him...
Every breath, every step... dripped off regret... even the atmosphere around him was drunken deep in sorrow and regret... the look in his eyes as he used his spiritual energy to heal her... and when he finally worked up the courage to look her in the eyes to ask if she was hurting...
This scene touched me.