Demon Slayer: The Perfect Creature

This story is an expansion of a little idea I had:

While searching for Kibutsuji Muzan, Yoriichi Tsugikuni unexpectedly runs into his long-lost older brother, Michikatsu Tsugikuni.

Unaware that his brother has become Upper Rank One, the Sun Breathing user notices that he seems to have settled down. Yoriichi returns to Michikatsu's home with him and is shocked to discover the progenitor of demons, Kibutsuji Muzan, in his brother's house.

What Sun Breathing finds even harder to believe is that wisteria and sunlight seem to have lost their power over the progenitor of demons. At the same time, his brother treats Muzan as if he were his wife.

Yoriichi Tsugikuni: "?!!"

Warnings:

1. A little self-indulgent idea. As someone who loves beautiful faces, I adore the Boss.

2. Expanded from a little idea. Severe OOC, beware!

3. Lots of headcanons. The author's cat ate the logic. For example, the Boss is now completely unaffected by sunlight and wisteria!

4. Kokushibo absolutely adores the Boss and obeys his every command.

5. Kibutsuji Muzan has been given a mischievous streak.

6. A sweet little romance: powerful, devoted doglike subordinate x arrogant, conceited, mischievous Boss

7. The author is fragile and writes out of love. No personal attacks or attempts to start arguments.

8. The main story is complete. Updates for the extras are irregular.

Message: It's not bad when the villain is evil. It's bad when the villain is handsome.