CLASH (Steam key/Region free).

http://store.steampowered.com/app/416040/
Earth is in the grips of a bitter cold war - nuclear armaments are armed and ready to fire should either East or West make a move. World leaders look to the skies for answers, and in a manner of speaking, an answer is found. An impossible mineral, a compound of elements that fits not into our understanding of the universe, has been discovered in the deepest reaches of space.

This impossible mineral begins to revolutionize technology - first being developed into weapons in order to control the spaces in which the compound can be found. But neither side wants to see the other gain control over supply.

A distant solar-system. A fight for the survival of billions. That is where you come in.

"Action meets strategy in a small indie multiplayer online battle arena. Clash takes a break from the classic weapon based shooters and offers players an ever growing variety of skills to choose from to create their own builds and team strategies." Good old-fashioned arena combat!