My Big Cousin (Anime Crossover)

The male lead has a lot of older cousins. Imagine someone suddenly calling all these characters "older cousin" in the middle of a battle. Everyone would be completely baffled, and the whole thing would instantly feel much more down-to-earth. Let me draft a blurb first. "That jerk Dazai actually has relatives? I thought he sprang out of a rock!" Shocked. Dazai: "..." "Does the Cloud Recessive Committee Chairman really have a cousin like this?" Doubtful. Hibari: "Hmph." "Muzan's cousin is actually human! With Muzan's personality, shouldn't he have wiped out his own clan?" Sleep-talking? Muzan: "...I've killed him plenty of times." "Breaking news! Natsume's distant relative is actually a great yokai!" Natsume: "He's human, trust me." "So he's the cousin of Zero and Ichiru Kiryuu. Wait! How can he fly? Are we sure he's not a vampire...?" The Kiryuu brothers: "Emmm." A story about claiming relatives everywhere. The male lead has low EQ, can't read the room, is oblivious, and is a total straight arrow, lol. A laugh riot. I think writing comedy is the real test of writing skill. (Serious.) Theme: No matter how many hardships you go through, face life with a smile