I swear I remember there was this one fic in the library or review board with a dimension traveling riddle, but I can’t find it. Specifically, the riddle that dimension travelled was mentored by Dumbledore, b/c he got caught opening the CoS which changed his trajectory. He then became the professor for defense against dark arts and eventually comes into conflict with his counterpart in the regular universe. If someone remembers the title that would be a godsend.

 

It's rectifier by niger aquila