
Chill....
He was imprinted, so he was mentally unstable. He should have died back then, when Areoc died, cause being imprinted means he is bound for life.
Hatred and love are mixed up because, from what he believes, he needs to be loyal to Rapiel no one else. Thats one reason why his love turns to hatred, and another fact is that he can't see his imprinted omega (Aeroc).
Kloff only lived because he needed to take care of their children. But as the years passed, he was bound to break, causing him to become a mad man..
But the other part you complained about is also true, though on my part.
I hated it when Areoc had gone through something horrible while pregnant.
But I am being forgiving now cause I read the novel... Heheheh...

The imprint made him crazy. It was established before the birth of the first kid, Clough’s obsession of Aeroc did all of this.
The reason he became cruel was because he didn’t spend much time with Aeroc, the imprint twist your thoughts and amplify your emotions. It’s the reason why he was always looking for reasons to beat up or torment Aeroc. It doesn’t excuse his actions, but it really played a huge role in why season 1 is messed up.
After Aeroc died.. it became worst, because he killed his omega. The imprint tormented him for years, like at first he kept himself busy with work, and the kids… but as one by one the kids were married off and he didn’t have anything to do. He started hallucinating.
Unfortunately it’s easier to blame the dead. Rapiel is forever immortalized as this kind poor soul who died because of Aeroc. And now Aeroc was taking away his children from him. So he destroys his tombstone trying to hurt Aeroc, but instead severely injures his son.
He couldn’t admit that he fucked up. His loved Aeroc, he freaking confirmed that in his own return and side-stories. But pride prevented him in being honest, because his revenge was stupid to begin with. His marriage with Rapiel was a farce as well. If he had been honest, he could had been happier with Aeroc. But pride…
Ah so you named your first son after your "beloved wife Raphiel" huh? How nice and thoughtful of you.... AND YOU STILL BLAMED AELOC WHEN HE DECIDED TO END HIS LIFE AFTER HE HEARD YOU SAYING "he take after my wife" WHICH HE THOUGHT IT WAS RAPHIEL!! (actually is) AND YOU BLAMED HIM FOR TRYING TO END IT SO FUCKING **EASILY**!!! and just because your first son find out your horrible truth you DESTROYING HIS GRAVE ROCK!!! (+plus killing his another son. I'm sure he won't get up from that) I thought you reflected on yourself after his death... but I guess I was delusional. AND IN THE END YOU WERE STILL TRYING TO REPLACE AELOC WITH RAPHIEL IN THE FIRST PLACE!!! and force feeding a pregnant person? FORCE FEEDING FUCKING PREGNANT PERSON!!!? HAVE YOU ACTUALLY LOST IT?! WHAT KIND OF MESSED UP LOGIC DO YOU HAVE TO HAVE TO THINK YOU CAN FEED PREGNANT PERSON WITH SOMETHING THAT DISLIKE!!? enough to get traumatized AT THAT!!!