Warframe

Wake up, Tenno.
Warframe is a lighting fast, stylish, free-to-play third-person perspective cooperative action game taking place in the industrial complexes, bases overgrown with plant life, and ancient ships lost to treacherous infestation. Cut down dozens of enemies, craft tools of war and devastation, upset the fragile balance with the power drawn from the Void. Explore how the Origin System has changed during your slumber and look within yourself to find more power.
And remember: ninjas play free, but work great in teams.