From the official release announcement:
"One side razes everything just for fun. The other side obliterates entire nations to uphold the law. Unfortunately, there’s no third side.
Avoid getting caught between a rock and a slightly shinier other rock. Suit up with Warden Nautilus and Sivir or Marauder Warwick and Ashe, available now in the League of Legends store for 750 RP each."
Marauder Ashe and Warwick
Warden Nautilus and Sivir