Leviathan, Mass Effect 3′s first proper singleplayer DLC, is out today.

The expansion sees Commander Shepherd exploring undiscovered parts of the galaxy in search of the titular being, played by voice actor Anthony Skordi.

“As unexplainable events begin to unfold, Commander Shepard and crew must travel to unexplored locations in order to piece together a shocking theory that could turn the tides of the war against the Reapers,” said BioWare.

The DLC also feature various weapons to the campaign mode that were once only available in multiplayer: the AT-12 Raider Shotgun and M-55 Argus Assault Rifle.

Leviathan is available to download on Xbox Live 800 Microsoft Points, or Origin or PlayStation Network for $15.95.