KR Novel: I'll do that marriage

Who the hell is that white-colored long-haired dude? What's his deal? 

Thank you so much for the spoilers 

Any ending spoilers ?? 

spoilers please 

Any spoilers when she confesses she loves ml? I just got to the part in the manhwa where he asks her if she does but she doesn't give a proper answer. 

So I just saw the recent raws (episode 26) and I just mtl, but I still don't really understand what's happening. Like are they having a contest/bet and why? 

will there be any villain? or what is the next conflict for the ml and fl to cope with?  @chax412 

no particular spoiler but here's what I know /// Her name is Leylin / Raylin, she's Lilianne and Bastian's sister. She's the one with dark blue hair. She's the legitimate daughter of Duke McKellion - unlike Lilianne - whilst she truly cares for her sister, that she considers equal no matter the status and origins. She has a lover and so she didn't want to marry the emperor in the og timeline. That led to her trying to flee to her lover the eve before her marriage with the emperor, which was the night she committed suicide after her father the duke killed her lover. In the 2nd timeline we learn that she's been on a relationship with her lover for about 1 year and a half. And dats all I know so far