Great fight with the back and forth- just what I like to see. Did not expect Nezuko to show up in a useful capacity, but she did, and possibly got some arbitrary powerup? Said powerup also being from a girl into a woman, apparently...

Interesting that the sun breathing (or whatever style Tanjiro was using) was making him cease to breathe here.

Is the other demon Muzan 'lost' to his influence the girl demon from s1 who is collecting the blood samples to reverse demonization?