Chapter 403 is now available for reading. I had to pull myself back from the previous comment knowing that the fight wasn't over, but I cliffhanged it as though it could be. Though I'm not sure how much of a cliffhanger it was felt. There was not much indication that the demon would be more than a chapter encounter. But he is the big encounter for Yumi in the mini-arc.
As mentioned, this starts to bring out some complicated elements and feelings for Yumi. The fact that she is actually having fun while fighting someone is something that bothers her. She is starting to lose who she was from the beginning and being dragged into the world of Yuki and Seiji, which in a way is something that she wanted. She wanted to be of use and able to stand next to him as an equal. Though the price of wanting that could be more than she is willing to accept.
Since the whole chapter is largely nothing but the fight, I tried to keep creative with the different things going on in the battle. Keep it very focused on each action this time around rather than more broad strokes. The actual fight is fairly important sense it does start showing more of what Yumi is able to do while in battle. And as things go on I can use it as away to show her progression and the way she changes in a fight.