
ajshxdbeksk WE HAVE OURSELVES A TSUNDERE YANDERE!!!!
*cues best of both worlds* (づ ̄ ³ ̄)づ

He is certainly possessive but I don't find him to be a yandere. If he was, he would be looking to get rid of her family so that he can have her all to themselves. Yandere's don't think about the feelings of the person they're yandere for. They only think about themselves and their obsession. The beast doesn't have that sort of unhealthy yandere obsession.

Plus he is a dangerous person with little regards towards other people's lives. He easily kills people without good reason. That apathy and disdain towards human life makes him great for an extreme yandere. However, he prioritizes Yeon over himself. He could've kidnapped and locked her up but the story would never go there because he's not a yandere and to him Yeon's wellbeing is #1. He's not a victim of that yandere obsession.

The key to a yandere is that they start out by falling in love with like anyone else and then they become unhealthily obsessed with the person they like. How far they take it is up to them and their personalities. However, there is no such unhealthy obsession in this manhwa as of yet (including the raws)
Here I'd like to present Actress of the Year (๑•ㅂ•)و✧