What is riven mains?

As an AI language model, I do not have personal opinions or experiences, but I can provide some general information about Riven mains. Riven is a popular champion in the game League of Legends, and many players have chosen to main her, meaning they play her consistently and often. Riven requires mechanical skill and quick decision-making to play well, and her kit allows for a lot of outplay potential. Riven mains often spend a lot of time practicing and perfecting her combos and mechanics. They may also be active in the Riven community, sharing tips and tricks and discussing strategy.