i don't really think ino had a choice because female lycans are really rare and since hwa gok was one but had already marked lee bin who was a vampire, he couldn't become the leader of the lycans ... so he tortured lee bin to give up hwa gok but kakia came to save lee bin and they met then. and then ino decided to become a spy for kakia in trade of him saving his life, turning his back on the actual lord lazelle and that's where we are now
yep! ino had a brother named uno who was a female lycan and his lover, nara, was actually supposed to be ino's mate but fell in love with uno instead. they had a child who is seolhyun but they were both killed by lazelle (lord of the lycans and kakia's ex) bc they went against the rules of the lycans. hwa, seolhyun's love interest, is the son of lee bin and hwa gok which is the main couple we see at the beginning. feel free to ask more :)
and right now we're at a flashback stage because this is when seolhyun is a kid. kakia (lee bin's father, not biological just the person who made him a vampire) and ino met because ino tried to kill lee bin for being with hwa gok who was a female lycan, and then kakia came to save lee bin. female lycans are the only lycans able to reproduce and are rare so that's why ino wanted hwa gok so bad so he could become the lord of the lycans. however he failed and kakia saved ino's life at the expense of him becoming a spy against lazelle (ino and lazelle were at the church caring for the lycan children) because lazelle was killing vampires due to his jealousy bc kakia started turning others into a vampire (lazelle was kakia's ex lover and the first "child" of kakia, he is a lycan now)

Or I lack understanding or the story is pretty inconsistent? Wasn't Ino the one that wanted to mark Hwa Gok and that tortured Lee Bin? I thought he and Khaki met during that time and since them started the relationship but now it seems it goes from some time before that.... I'm confused AF (︶︿︶)=凸