If you're wondering why Zenitsu changed in Demon Slayer, we've got you covered. Here's what you need to know.

Zenitsu does not awaken the demon slayer mark, defeating Kaigaku with a new technique instead. To unlock the mark, one must survive life-threatening conditions and have contact with a marked demon ...

If you're wondering what was in Zenitsu's letter in Demon Slayer, we've got you covered. Here's what you need to know.