I think it started changing the minute Gozu interfered, little by little, like the maiden who's supposed to be nice and all and supposed to go to that place, and the dragon that supposed to destroy the town, and the mage, the unicorn that supposed to stay, etc.
But how he is supposed to change someone gender before he transmigrate?
Manga isekia BL logic ╮(￣▽￣)╭ .. Honestly idk, I hope they explain that, but knowing this manga that explanation will take a year or months lol(〜￣△￣)〜
welp just like gozu said...
this is a world of BL with MAGIC after all
there's no point trying to apply logic to it
(￣∇￣") ┑(￣Д ￣)┍
Did they change history up to the point , the Saintess is a guy? (≧∀≦)
I wonder if he got Isekaied there too?