Kaigaku was a Demon Slayer along with you. You guys didn't get along, because he was very annoying, but he acted like that because in truth, he was in love with you, but he was ashamed to admit it.

You were both assigned the same mission, so you started walking down a dirt road. While you walk, trying to ignore him, he teased you, laughing at you, but he loved to see your frustrated face..

"Haha! What is that haori? It's so ugly!"