I Want to Transmigrate Today, Too

My name is Kataoka Shiro. One day, a classmate suddenly joked that I was going to transmigrate. After carefully weighing where I would go if I really did transmigrate, I decided: another world, of course! And if possible, one full of cat-eared girls! Who doesn't love cat-eared girls?! But I never imagined this would happen. I didn't transmigrate to another world, and I didn't meet any cat-eared girls. Instead, a cat-eared boy (?) transmigrated into my home... Coach! I object! He's stealing my part! The sword tsukumogami Nansen: What?! Just because you summoned me, you think you can get cocky? I'm only like this because of a curse, meow! Coach, look at him! He even has a verbal tic! Why is his style rating so high? I object! I'm the protagonist, right?! ...I really am the protagonist, right? Things to know before reading: 1. The protagonist simply thinks cat-eared girls are cute. This may be a lighthearted yet serious story (emphasis on serious). It will probably alternate between first-person and third-person narration. 2. No CP. The protagonist neither flirts with nor is flirted with, and there are no unrequited crushes, either one-sided or reciprocated. His relationships with everyone, people and blades alike, are purely straight-guy friendships. 3. The protagonist is not a Saniwa. He just happens to have Nansen. He won't develop any identity beyond that of a male high school student. 4. He does transmigrate, but unless something clearly exceeds the bounds of his understanding, he doesn't realize it. 5. The protagonist is an ordinary male high school student with no special abilities. His strength, stamina, intelligence, and everything else are average. He's the kind of guy who hides magazines under his bed, only for his mom to find them while cleaning and humiliate him on the spot. 6. For now, I plan to cross this over with Katekyo Hitman Reborn! and Natsume's Book of Friends. If I think of other series to cross it with later, I'll add them. There may also be some more fantastical elements. Theme: Friendship can only be gained by meeting sincerity with sincerity.