Accidental Difference

Marked ones appear through resonance, in the original story it was due to the Kamado Family that they resurged, but what if we were to cheat a little and bring the marks early into the story through...unconventional means. (It happens through Giyuu couse he's my favorite, there will be other one-shots focused on other characters)
The means of course have unexpected consequences and a brighter future.
Or
Max potential fem!Giyuu swaps bodies with a more cannon accurate counterpart.