Cosplaying as Doma in the Warring States Era, I Use Science to Slay Demons

A Tong, cosplaying as Douma, walked out of a convention and transmigrated to another world. Bad news: My body, eyes, and hair all changed to look like the Douma I was cosplaying. Good news: I was cosplaying the Upper Rank Two, human-only edition. (My wig maker didn't have time to splash my expensive wig with red dye.) Bad news: I don't have any yen on me. Good news: I have no shame now, so I can beg for food without a care. Bad news: I don't have any strong emotions now. My heart is as calm as still water. Good news: My mind is perfectly normal, and I know all about bonds and obsessions from my memories. Bad news: I got stuck with a leaky, battle-damaged Merit System. Good news: There's a secondhand goods marketplace in the System. Then A Tong, trying to build up merit so she can get home, finds herself staring at someone she rescued from demons. He's wearing clothes from the Warring States period and claims to be the head of the Tsugikuni family... * Demon: For Lord Muzan's sake! I'll eat and eat and eat and eat humans. The next Upper Rank will be me! A Tong: So I can go home! I'll save and save and save and save people. I'll protect the next victim! Huh? W-Wait, why is everyone calling me their leader and saying I'm the Child of God? I told you not to get caught up in feudal superstition. This is all science! Hey, System, listen to me. I'm really not running some evil, illegal organization. Don't deduct my merit! Reader's Guide: 1. A Tong's emotions have been dulled, but her worldview, formed over more than twenty years, hasn't changed. 2. Set in an alternate history. *Coming soon: My Cursed Technique Is "Screenwriting" [September 3, XX. My younger sister Miko has been acting a little strange lately. She even asked if I'm scared of ghosts. Something like that couldn't possibly exist.] [September 4, XX. On my way home from school today, I saw a strange person with silver-blue hair, stitches across his face, and mismatched eyes. I chased after him.] [September 5, XX. There really are ghosts in this world (crossed out) curses! Miko was telling the truth!] [September 11, XX. I have a cursed technique of my own now, and it's just like "screenwriting"! I can write and arrange anything about anyone however I want. It sounds so cool!] [September 12, XX. A delinquent at school gave me trouble today. I saw him bullying Junpei and others before, too. A bastard who bullies people as he pleases deserves to jump off the school building and repent for his mistakes.] [He really did jump.] *Coming soon: The Tsugikuni Twins Reincarnate as Uchiha Theme: Make the world a little more complete.