It's kind of amusing to remember that the original Destiny was allegedly supposed to have a ten-year plan in place for adding new content, and yet here we are, 5 years later, discussing rumors about Destiny 3.
Destiny developer Bungie only recently managed to pry the shooter franchise from the fingers of Activision, and now it seems like it might be working on the next entry in the series. Granted, the existence of the third installment of the Destiny franchise hasn't been confirmed as of yet, but these rumors come straight from a well known Destiny leaker.
Reddit user AnonTheNine has been leaking Destiny news for a while now. He leaked information about the Thunderlord (an exotic weapon) making its return to the game, as well as the addition of new subclasses for the Forsaken DLC. So, while this news should be taken with a dump truck full of salt, it is coming from someone who's been right in the past.
The Destiny 3 leaks so far give details about a new race called the Veil. They're referred to as "Astrodemons" and are "the true servants of the darkness." In terms of physical characteristics, they have "dark greenish skin, sharp claws" as well as "a distinct stench of 'wet earth.'" They sound like a fun bunch.
They may be the new big baddies in the third entry of the series. Apparently, their goal is to resurrect their long lost god who was slain in a battle with the light. To do this, they need the Traveler to awaken so they can use its power to give their god new life. Destiny has kind of a silly story.
Other details involve new gameplay additions, such as darkness-based powers. Considering that Guardians are supposed to be followers of the light, it'll be interesting to see how harnessing the power of darkness will affect the story. Possible new inclusions also involve changes to The Crucible, and some Planetside-esque PVPVE areas.
The game is apparently aiming to target for a more "hardcore" audience, with a higher difficulty, more planets, and more RPG elements. There will also be a stronger emphasis on story this time around. Now that Bungie doesn't have to worry about appeasing its corporate overlord Activision, it may be emboldened to take more chances -- and this harder, more plot-focused Destiny may be a result of that.
Again, these are all rumors. While this is coming from a somewhat reliable source, it is still just speculation coming from the internet. However, it is interesting to note that AnonTheNine has deleted his Reddit account, so maybe these leaks got him in hot water with Bungie?
Destiny 3 is rumored to launch in the fall of 2020. If that release window is accurate, then you can probably expect at least another year of content from Destiny 2: Forsaken.