Werewolves (a Ninjago AU)

(I only own the plot none of the Ninjago characters and this is basically a AU)

Cole is the alpha of his pack and has lived in luxury his whole life though he isn't one who hasn't had hurt in his own way. His pack is the most powerful one in the world and he's one of the most feared yet fair leaders of the werewolf community that took up most of the world besides some human villages and towns that stick to their human selves except for one night a year. Every end of summer each town offers female humans in towns squares between 18-30 for werewolves to see if they are the mates of any werewolves and were only to be taken if they were the mate and only the females are offered. Cole has no mate and he needs a Luna too help him rule his pack because he can't do it alone and it's starting to weigh him down a little. So what does he do when he does meet his mate, but it's nothing like he suspected?

Kai's a orphan with his little sister his mother and father were killed by rogue werewolves during a attack and topped with the possibility his only family might be offered to one like a slave. Well he grew a deep hatred for them and everything they were. When Nya turns eighteen she's sent as one of the offerings while he's in the church. But scared of loosing his only family he vowed to protect he snuck out of the church to stop his sister from being taken like so many others. But what happens when he gets caught by one of the werewolves, but doesn't die?