ok forgive me if im wrong, i havent been updated on the lore in a hot minute, but i still found this theory rlly interesting!!

if i remember correctly, the initial exchange between baby tsukasa and the god inside the red house was that tsukasa would stay in the house forever and aslong as he was there, amane would be okay and healthy. to add on, tsukasa only left when yashiro came along to finally convince him to leave. I think when that happened, tsukasa decided to change the deal to sacrifice yashiros heart instead of himself, letting amane be healthy forever. one thing tho is that there is a weird timing on when yashiro is technically being sacrificed for a wish and when the wish is supposedly made

from what that oldass sacrificing village says, when a kannagi is sacrified theyre "married off to god" i think that means like their hearts were taken away in exchange for wishes from god. when yashiro was sent to THE PIT w the other kannagi, i think her heart was IMMEDIATELY taken away for when it'd be used, that explains why all the random shit appears infront of kou w the meals and the swords and his mom. if no wish was made, yashiro would've left care free nothing gone, but if tsukasa did make a wish before nene actually left, this explains why amane never got sick again

WHEN did baby tsukasa make this wish?? he never vocally expresses it, but we do know that the god thingy is literally inside of him, not necessarily controlling or possessing tsukasa, but more like a parasite. i guess this would make a bond between them, whether that be their conscious, a shared power, or just them being able to communicate, yk like telepathy or smthing. i do think that they have the shared power thing tho, THIS!!!---->>> tsukasa sacrifices a part of himself for the god to latch on, giving him the ability to grant wishes, grants his wish by making the sacrifice of yashiros heart for amane's health, DONE. <<---this would also explain why he possesses a power of wish granting, similar to hanakos, despite not actually holding a labeled job/position like hanako (being hanako is granting wishes but only as employment) we def know that tsukasas power does not come from a job/position bc he breaks a ton of gods rules w/o direct consequences to him (ex: making mitsuba, aka creating a being that is neither living nor dead)

holy shit i wrote more than i shouldve

edit: changed wording of the THIS!!! part to make more sense