Through a series of seven pictures, Riot has teased their next champion to enter the League of Legends fray. Quinn and her bird companion Valor are some sort of Demancian bounty hunters. These pictures show pages of what I assume is her journal which tells the story of an assassin man hunt. Demacia thinks the killer is Talon, but Quinn has more insight to it. Of course Garen marches right past the killer's camp. I won’t ruin the short story for you but check it out via League of Legend’s Facebook photos – Demacia Needs a Hero.
From the looks of Quinn, she will be an attack damage carry. Given the length of time between the last ADC, Quinn is certainly a welcomed addition. I would assume from her appearance and story that Val will be tied to at least one of her abilities. While no abilities have been listed yet, I assume Riot will put something on the LoL page in the next few days.
I know people are already excited for Quinn. Folk have been looking for a new ADC for some time now.