Horrible History of household Hell: Ending A?

[taxicabmessiah]

I'm able to get to the final fight with all of the required items, but I don't see the extra option to sacrifice my ally anywhere. I've tried this twice now, but it didn't work either time.

Is my game just bugged or am I looking in the wrong spot?

[Boo]

It should be right above the Special Run Away option (Not normal escape, the "No Hope!" escape in the offensive actions menu)
You probably need a weapon equipped too, Ritual Dagger if you're going for the Achievement

[sleepingcrows]

The option to "attack your ally" or "flee" are in the Offensive Actions to the left. It could also be what kind of ally you're bringing in with you too. I had a student with me and Masafumi and when I attacked, the game killed Masafumi even though they were the second ally I recruited, so it may be you have to bring in a named/special ally rather than just a student. Hope that helps

[taxicabmessiah]

I had Kana with me both times, so I think the issue might be the lack of a ritual dagger. That makes the most sense.

Thanks for the answers, I'll try it out next time I get this mystery.

[Marmorkatze]

It’s not the Ritual Daggee, but Kana. Kana is notified as being „important“. The dagger is only needed for the achievement.

Just pick Mizuki and recruit a random student from school.

[Scrimmjob]

I was able to sacrifice Kana during this quest.

[Edfrapine]

Originally posted by Scrimmjob:

I was able to sacrifice Kana during this quest.

She wasn't always marked as important. This was a change that was made in a recent patch. You also don't need a weapon at all unless you're going for the achievement.