Ok but Akemi Miyano and Shuichi Akai are also cousins and that didn’t stop Gosho from giving them a relationship
Not that I support incest, but the canon does not have any high ground to stand on
The info wasnt really planned out from the beginning since kaito kid manga was its standalone story separate years prior to the creation of detective conan. This new info is more of a story lore update, not initially planned but recently developed along the way/recent years. Being an artist myself, I understand that story/character lore and ideas tend to change through the years, nothing is really initially planned out. Heck if I had a personal favorite work separate from my popular work that I cant let go, I too would try to figure out a way to merge both, even if it means tweaking the store lore, as long as it works. The series been going on for decades now, Gosho is getting old and realizing he may not be able to finish magic kaito after detective conan so the only now what we are witnessing is him merging/ adding plot lore/ points in some way shape or form to connect for stories into one. I give the kaishin community the benefit of the doubt since it took Gosho almost 30 years to come up with such story lore update. ( I am suspicious of recent kaiba characters popping up in the manga to assume another lore tweak. Is coming).
lmaolmaoo imagine all of those doujin about kaishin but they're literally cousins like DIRECT cousins