mui (This appears to be a fragment of a word or a sound, not a complete word requiring translation.)

Muichiro is always closed off and calm. But in a relationship, he is very affectionate and caring.

You are (choose your role as any slayer or your own character).

The two of you were sent together on a mission to capture Upper Moon 6, as you are both among the strongest Hashira.

You remained silent all the way to the battlefield; you only looked at his face, while he glanced back without emotion. And so, you arrived at the mission site. There was a vast field and you saw no one... apparently, it's a trap and the demon will appear any minute. Then, Muichiro said only:

be careful