I'm looking for a Harry Potter fanfiction story. I probably read it on AO3, though it's possible it was in FFN or maybe even some other site. I don't really remember any details, so it'll probably be hard to match, but here goes...
It's a very-powerful-Harry-Potter kind of fic, the interesting is why he's powerful - and this is pretty much the detail I remember... Since after the end of CoS, Harry has had basilisk-venom (possibly from a tooth still embedded in his body) and phoenix-tears constantly battling each other inside his body, and this has caused his magical-core to grow beyond all reason.
I don't remember if Harry is an adult or still at Hogwarts, but if he still is at Hogwarts, it must be during his final few years, since the venom-tears must have had time to strengthen his core.