An Unconventional Muzan [Crossover]

Blurb 1 If Muzan had even a little sense (and he has five brains, no less), he could rule Japan. So why has he been such a loser for a thousand years? The answer is simple: Kibutsuji Muzan is played by a veteran employee of the Transmigration Bureau, complete with a full benefits package. Muzan (fake): Playing with the Demon Slayer Corps (and getting sliced up) feels way better than being in the Infinity Castle. Being there with just one demon is so boring. Doma talks even more seductively than Tomioka, and Upper One never wants to play with me. But once I joined the Demon Slayer Corps, everyone was talented and so nice to talk to~ And so, the original plot outline vanished without a trace. Blurb 2 You can expect to see: A little Yoriichi, flirted with and lured into becoming Upper One by Muzan. A white blood cell from Cells at Work! who transmigrates into Cells at Work! Code Black and cross-dresses online. A seemingly sweet but secretly ruthless Senju Hashirama (fake), trying to achieve world peace with one slick move, teaming up with his nemesis to blast through the wilderness with dragon flames and rock music. An immortal old-timer (?), a sunny fake grandpa, reclaiming all sorts of deadly tragic endings one by one, all in the name of friendship. No CP, but the protagonist is a total loser, so pick your favorite at your own risk ( 'ω' ) P.S. I'm a beginner, so progress will be slow. I'll revise the earlier chapters later, so feel free to start from Chapter 3~ I'm still a high school student, so updates will be whenever I can manage. They'll become regular after graduation. Please add this to your favorites so you don't lose track of it! Please comment! (A comment-loving author is here with mouth open, waiting for food!) [P.P.S. This is just for my own amusement, and I'm writing what I want to read. The whole thing was dictated by voice, so the wording may be a little rough, and I might occasionally misspeak. If you see names like Demon Samurai Muzan or Kibutsuji Muzan written wrong, those aren't names for the loser boss, but for the unlucky actor. It's definitely not because I'm too lazy to think of a name for the protagonist! (Note: Once he officially plays the boss, Kibutsuji Muzan will be his name.)] Theme: Being ridiculous is contagious, especially when you've been ridiculous for a thousand years