Dude, just because you didn't understand doesn't mean there were plot holes and didn't make sense lmao. I suggest you read it again and read between the lines.
It was definitely implied that the dad was a pedophile. He involved Theo to control him and to test him (basically see if he's a worthy heir, also to make sure that he has blood on his hands so he can't easily try to report the dad since he's now an accomplice). The dad and Cedric both have golden hair, they could be the golden sun (trapped beneath Cedric literally due to being sexually assaulted).
It's left vague whether the dad molested Theo but my interpretation is it didn't get that far, though the BDSM snapping and sharing in the assault of other children was sexual in nature.
Theo was forced to help his dad during Paradise, hence his sins. He didn't see ghosts until his mother died and he lost his only support. It was all psychological trauma but you can also say that the tragedy of the house took on its own life, like you'll see in a lot of haunted house stories.
This is just my shitty understanding.
Tbh, idk wtf the father did, but some ppl are sick in the head. There's bunch of killer that kills for that sake of it. As for Theo, I think his father forced him to kill since he got caught.
Golden sun probably refers to Cedric hair colour, and also refers to how he's the light for Theo's life.
His father didn't have sex with Theo before he run away. It's after he went old, he kinda want Theo, saying hes beautiful and shit. When he implied that he wanted to sleep with Theo, that's when Cedric lost it.
As for the ghosts, both of them apparently can see it. As for Theo, it's probably out of guilt or just cuz the spirit of the dead lingers around the paradise. Haunted place is haunted because all the people there didn't die in peace.
Theo is a very disturbed child, especially mentally. All he wanted was to run away. He knows what his father was doing, what his father made him do was something he couldn't forgive himself. He's too scared to kill his father, the only option for him is to run away
Please explain... I'm sorry I need to clear something's out... What the cult fuck was the father doing? Was the father a pedophile? Having sex with kids and then killing them? And why he did Theo's hands bloody with killings? And the last line by Theo (forever trapped beneath this golden Sun?) Was his father having sex with Theo too? Oh damnnn (and the father saying I shouldn't have let go of Theo even if it meant for him to take the place of his mother? )Whaaat???? Theo wanted to wash of his sins that's why he left paradise? Or was he a mentally disturbed child... seeing his mother's and other children's corpse? Or was he really having some supernatural powers? Only thing made sense to me is Cedric and His revenge on his father! Nothing else made sense... I mean good art....thoda sa confusing hogaya lekin mere liye