@Shu_Yukihara Even though Chizuru tries to isolate herself, she's by some means, almost destined to end with Kazuya
But yeah, i see a major fallout between them looming in the horizon. And Mami will more likely than not be involved in the shitstorm. Ruka, if anything, is the weakest link and the most likely to have her resolution sooner than expected. Besides, her reasons to fall in love with Kazuya are the most stupid.
@curvedtree afaik, Kazuya is anything, but spoiled. Also, his family constantly shits on him (confirmed) and puts too much pressure on him with the whole "bring granny a girlfriend and let me see your children before i kick the bucket". A toxic environment and the social pressure influences your behavior more than you believe.
Rejection ptsd and being aware you're a piece of a shit when put next to a 11/10 girl like Chizuru only enable his insecurities. Kazuya can be an insufferable piece of shit most of the times, but it's not like he's that because of his own will.