World of Warcraft's sixth expansion is entitled Legion, Blizzard announced today at their Gamescom 2015 briefing.

In the story, the Burning Legion returns in "the biggest invasion of Azeroth ever," and players will fight off its hordes through a host of new features.

Blizzard revealed a new Azeroth continent, a fallen Night Elf civilisation called The Broken Isles that now functions as a portal for the Legion.

Demon Hunters, a new class in Legion, start at a high level and are available in DPS and tank varieties. They feature abilities including the laser-like Eye Beam, a dash attack, and a double-jump.

New weapons called Artifacts can be upgraded and levelled up alongside characters (whose cap is now increased to 110), gaining a wide range of powers and appearances.

Claiming it has "done dungeons a bit of disservice," Blizzard aims to improve and expand its range of dungeons in the expansion. At least two new raids will be available, featuring seven and ten bosses respectively, one of which allows players to face antagonist Gul'dan.

Finally, the honor system will be overhauled, making gear less important and adding PvP-specific ranks and talents.

The announcement comes as World of Warcraft subscriptions reach a nine-year low of 5.6 million, according to Activision Blizzard's Q2 financial report.

Legion has no official release date, but a beta test is set for "later this year".