Ok, so a lot of this I’m referencing from My Name Is Byf’s video on Destiny 2 (I highly recommend you check out his channel)
So from the “rally the troops” trailer, we can see that the Red Legion has attacked the tower, destroyed all of Cayade’s (and our) stuff. But if you play close attention to the trailer, we can see some sort of dome forming over the traveler.
If you pay attention also to the Cabal Phalanx sheld right after, it seems to have the same sort of pattern. So the question is, why are the cabal trying to seemingly trying to suppress the traveler, when their main enemy is the Guardians?
Well if you look at the Cabal lore, it references the ghosts, or dead persons as the gimore states.
The Cabal know that the Guardians are immortal, but they also know that the ghost are their source of said immortality.
And the Cabal know about Traveler, and that the ghosts draw their immorality giving powers from it.
So if the Cabal suppress the Traveler, they cut off our powers and immorality, right? Well not exactly.
So going to back to the trailer, we can clearly see Ikora Ray (warlock vanguard) using stormcaller on a Cabal unit. But this is impossible right? Since the Traveler’s light has been cut off.
Actually it isnt, but a bit of lore first.
(And I semi-quote Byf on this next bit, with a It of my own theory in there)
“Stormcallers are incredibly rare”, because you literally have to control the flow of Pure Ark Energy from an Ark Storm and while respecting its raw power. This feat would kill most guardians.
“Nightstalkers are almost unheard of” a mystery of the night, you could say. Hunters reach into darkness of the void, seeking its secrets and the unknown. And they never come out the same, because the void rests on the line between the Light and The Darkness. One wrong step, and you are gone. Forever.
“Sunbreakers are a mercenary group, unknown to city for centuries” the Sunbreakers are actually the most mysterious of the Three. Since they have a (possibly) large number of Titans already using the ability. But since they have no connections to the city at all, it is completely unknown.
When Titans go to summon the hammer of Sol, they draw power Directly from the Sun, yes the giant ball of plasma at the center of our solar system.
So what does all of this have to do with Ikora ray using stormcaller during the trailer?
Stormcaller, Nightstalker, and Sunbreaker do use Light, but not the Traveler’s light. That also explains why in game they were added later than the original 6 subclasses and why they require there own missions, because they are completely different than any other ability than we as Guardians are use too.
This may explain (in my opinion) what and why the Cabal are invading the tower in the first place