Dota 2

Dota 2 is a multiplayer online battle arena video game and the stand-alone sequel to the Defense of the Ancients (DotA) mod. With regular updates that ensure a constant evolution of gameplay, features, and heroes, Dota 2 has taken on a life of its own.

Each match of Dota 2 involves two teams, both containing five players and occupying a fortified stronghold at either end of the map. Victory is achieved by destroying the enemy's Ancient, a building that is invulnerable until certain objectives are achieved. Each player controls a "Hero" character and focuses on leveling up, acquiring items and fighting against the other team to achieve victory during each match.
The previous match has no connection with the next match. All heroes are playable as in you do not have to "purchase/unlock" heroes to play them. The game development team try their best at balancing the heroes so that all heroes can be played in any match