Why has Yuvraj become negative?

As much as i like kunj , to be honest , i don't think he is the main lead. Yuvraj is kind of grey , not negative. I think the Cvs earlier thought that they would open the show with two lovers and their rival families but then they fell short of ideas and now they want to show how two rivals fell in love and then show the rivalry of families. So basically they want to redeem their earlier show keh start mien hee love wala idea... this is my personal theory... earlier the show was about how yuvi and twinkle loved each other and will fight off families but now the show will be about how yuvi and twinkle become lovers from rivals themselves and then fight off their families

the cvs have put this angle

I think he is playing a game with Twinkle to trap her per his mom's directions. He will go to any extreme for his mom. Mom wants that Twinkle's engagement breaks and Yuvi is trying his level best to make that happen. The fact that he thought to hurt Kunj and resorted to violence makes me feel he doesn't have the maturity to have a serious relationship with Twinkle. A decent person would have felt bad that Twinkle's mama was treated like that and wouldn't have beat up his so called friends the way he did. So in my eyes he is not the hero but a zero. Twinkle is better off with Kunj who is a decent educated person.

I think Yuvi was always meant to be a negative character. Granted not a completely dark character, but definitely one with grey shades in it.

No he is going to be the mentally ill stalker type lover, I wish twinkle sees the reality soon