I really like the character development of "Heewon"(the black haired woman) hope to see more of her, and how MC guides her to a 'better path' to revenge than becoming a brain less killer (MC said that it is a possibility if a remember correctly)
Also so far I really like who the other 'side characters' in general feels alive, the villain is calculating, his friends follow him, but are curious about his ability, even the off screen character (people in the train station) feel like they have their own thought, some are ok with the MC some are not some don't care and lost their will to live etc.