Recs for mutually destructive, unhealthy, codependent, toxic, obsessive or otherwise fucked up tomarry/harrymort fics

In the mood for some messy relationships. The more emotionally toxic the better. Pretty much no content warning is an issue as long they're mutually obsessed with each other by the end. In fact the more dark content the better.

Looking for ones set in the canon universe, but time travel/deaging shenanigans are a-okay! Complete only please, and prefer longer but I'll take any length. Also explicit if possible.

Thank you!!!