Nightbringer Yasuo.

Why the hell is it not called Duskbringer Yasuo to go with Dawnbringer Riven?

Not only does "Dusk" sound way more awesome than "Night" but dusk is the most natural antonym of dawn, with dawn meaning beginning of day and dusk meaning beginning of night.

Skins looks pretty damned neat aside from all that, but seriously. Duskbringer.