Again great chapter!
Musashi is struggling with this "victory". He cut him down, someone he thought would be incrediblely strong and it would be yet another duel about death, but this time he cut him down so fast he doesn't even know how it happened. He has come a step closer to becoming invincible under the sun, but it seems he has hit the point of why should he be doing it. At first cutting down men brought him a victorious feeling, but now he feels empty and maybe even regrets doing it......
Expressing his feelings/emptyness while drawing with water.....
Let's see how Musashi will coop with this mentally, because he is struggling right now.
I think we might get so see Otsu again and her confronting Musashi.....