Spoiler: So since Chase doesn't like using people for his rut, he has a lot of issues and one is blacking out and not remembering anything. So to "help" his brother and make him more open minded and willing to seek help during his rut, when they were younger, Grayson lied to Chase that he slept with their family dog while he was blacked out and that traumatized Chase. Grayson also did some other crazy disgusting shit in the name of being "helpful" but I dont remember those in detail.
Spoiler : adding to the one above, iirc Chase said he is waiting for santaclaus and climbed the roof so Grayson pushed him down the chimney to make him realize, locked him in a closet for hours because Chase is afraid of darkness, and throw away Chase's pet bird's corpse into the bin after calling Chase weird for having feelings like sadness and cried about the bird. Brought him to pheromones sex party and drugged him even though Chase hated that (ended up with Chase enduring himself every single time because he didnt want any of it) All for the sake of "helping" his brother. Thanks to that, Chase has endless trauma and has a very bad temper, and chose not to trust anyone.
He is sick in the head but, the entire family is actually sick. Chase was the most normal one amongst all lol.
It's a combination of Grayson's "help" (which really is problematic) and readers not understanding the universe/reading comprehension/bad translations/manhwa adaption.
What did Grayson do to Chase?? Why is he getting tons of hate?