Asriellas Father has always been a cruel person except toward his family unless they piss him off. With him being the leader of a mafia like buisness and being a yakuza it was always stressful for him to do things with family as well which caused a major distance between them. After Asriellas mother died though Cain became more pissed then ever. If anyone did anything wrong at all he would hurt them or something aroumd those lines. So basically long story short, Asriella never got the father she felt she should have had.
(Credit to the original owners of the artwork and YandereDev for Yandere Simulator)