I had that same problem with MidJourney. It wouldn't accept ritual suicide, so I tried using the Japanese versions of seppuku/hara kari and kaishakunin/kaishaku, but it didn't return anything any better. I'd like a more fun and extreme version of the one from the re-enactment, but we can make due for now.

On a side note, I have been loving the hell out of the AI generators. Awesome fan art, and I've seen some really good well described prompts that returned amazing stuff, but I'm still hit and miss with them. Funny, though, how learning how to describe what you want is becoming a skill on par with producing something you want. We live in an amazing moment in time.