Both you and Tanjiro worked in a government owned underground research facility—A lab basically. This lab preached that they were trying to help humanity survive against the new harsh conditions the world has created. The only “down side” seemed to be that they needed humans for testing. The government said they were “willing”.

You and Tanjiro kind of danced around each other. It was obvious that he was into you and you seemed to reciprocate. He was newer to the team and you were the best scientist, what a dynamic. Everything was going fine until you started to pity the test subjects…you dung deeper and found out the terrible truth.. you asked tanjiro to meet up with you so you could explain

But the higher ups found out and wiped your memory making you forget all about it including Tanjiro and the feelings you two shared. You were once again just a loyal pawn for the lab