Responses
there's also the fact that the satous Don't look like theyre in the same grade as the other MCs but i have no explanation for that other than what do you expect from an author who thinks it's fine to have an MC be attracted to his 1yo sister!!!!! i just wanted to be smug in the comments i wouldnt recommend reading this
there are four main characters!
satou atsushi: a kid who has the weird quirk of having learned cat/dog language before japanese for no reason. he met manato in preschool or whatever and theyve been friends since then. he dyed his hair (probably to match manato) in like junior high or high school.
satou manato: a brocon,, i didnt bother learning if they were twins or if shuu was older bc i hate incest. atsushi is his best friend.
kousaka youji: brainy siscon and massive pedophile. learned about the satou friends bc of rumours and used his brains to make a forum-style website to collect the rumours ab them in one place or smth bc he admired them. skipped out on school bc he didn't feel like going. basically a shitty person
yoshioka(?): golden lab of a human, super clingy and annoys all the other main characters. there is no other point of interest to him
satou manato is in love with his brother shuu (shuuta?? shuuto??? i already forgot his name). manato basically pretends to be sickly to get shuu's attention, had a yandere moment when he was little and shuu sort of avoids him since then even tho he holds lots of brotherly love for him
the main source of confusion is probably that each of the author's plot points have absolutely no connection to one another and that each fact we learn about the characters is really dumb and inconsequential where they would be important characterizations in another, better manga.