As the launch of Destiny 2 moves closer and closer, more is being revealed of the game, both intentionally and not. The latest leak is the game's achievement/trophy list, which reveals the name of the first raid, Leviathan.
Along with that reveal, it appears that the hard mode of the raid is no longer being called "Hard Mode" or "Heroic Mode" as it was in Destiny 1. It is instead referred to as "Prestige difficulty." It's likely to mean the same—modifiers such as higher-level, more frequent enemies—but it's interesting that developer Bungie has changed the nomenclature of the raid's harder difficulty in Destiny 2.
Only small tidbits are known outside of the name for this raid. Bungie has let out a short gif of six Guardians walking down a hallway, which given the player count is likely from the raid.
But as always Bungie is keeping the raid as secret as possible. The endgame PvE activities have always been the greatest mysteries in Destiny, daring teams to enter its challenges to solve puzzles and overcome the most mechanic-heavy enemies and encounters.
Bungie has said that the raid will go live within the launch window of the game, but has not clarified exactly what that means or given an exact date. Traditionally, raids have released just a few days after the a new expansion has launched, but it's unclear if that pattern will hold for Destiny 2. PC players don't get in on the action until October 24th, so Bungie may wait a little longer to help all of its potential fans feel included.
The developers have said the theme of the raid is "building a place you believe is real," but that has numerous interpretations. The name Leviathan usually refers to a sea monster, but it has been used in other science fiction universes to refer to both monsters and starships. Based on the fact that the villainous Red Legion has an armada of ships, it's possible that the raid could somehow involve a Cabal ship, but that's just pure speculation at this point.
Destiny 2 releases on September 6, 2017 for PS4 and Xbox One, and on October 24, 2017 for PC.