Fun Fact:
After Savathûn's resurrection, there is a lore tab where saint 14 brings immaru to the throne world, and proceeds to kill savathûn just about 50 times in a row

Have you noticed that Drifter's catchphrase is basically "Trust"? There's even a hand cannon called Trust that comes from Gambit. In Season of the Witch there's a new hand cannon with lore where Drifter muses over what Eris did turning herself into a Hive god. He decides screw everyone else's opinion, he's putting his faith in Eris. The name of the hand cannon is Kept Confidence, a synonym for trust... I love how their relationship has developed and the little details the writers put in this game

1:00:44 last season it was explained in lore, but Ahsa is what the Worm God's were before they became the Worm God's, they are called "Proto-Worms". The Witness met these Proto-Worms & offered them Darkness & corrupted them with it, turned the worms against each other other if they didn't join the Witness, Ahsa is a survivor

1:39:10 - So, "the 15th Wish", or the last wish, is actually a meta-narrative. When Forsaken came out, in the "Last Wish" raid, there was a mechanic called the Wall of Wishes. With this wall, you could input a bunch of codes that would do specific things. Some codes teleported the fireteam to a specific encounter, some codes put the raid in "hard mode", some even gave you unique narrators throughout the raid. There were 14 possible codes in total, but in our triumphs tab, it kept showing 14/15 possible codes. It became an urban myth in Destiny's community for a bit, with tons of folks trying to figure out if the 15th wish actually existed. Finally, Bungie decided to humor us: yes, there IS a 15th Wish. Savathun's Wish, one imprinted on her wings for us to find that CAN be inputted into that wish wall. A nice little easter egg to what was initially just a numbers glitch in our triumphs ;)

Game time is synchronous to IRL time. This was confirmed back in Season of the Drifter with "The Job" record/web lore. Where Aunor, a Warlock who only appears in lore is skeptical about how Cayde died saying in part "...We lost Cayde on a random Tuesday. And you all just took that Guardian's word for it?"

During the Festival of the Lost (Destiny’s reoccurring Halloween event) associated with this season, there’s a lore book showing some shenanigans Immaru got up to while being kept at the Tower. At one point, he gets it in his head that it’d be advantageous to steal candy, and ropes Archie, a robot dog made by Rasputin (introduced in Season of the Seraph), into helping him. The lore book this takes place in—“Tales of the Forgotten — Vol. 3”—doesn’t matter much to the greater story, but is a great read if you’re interested in the slice-of-life aspects of Destiny. The same can be said for the other Tales of the Forgotten books, as well as the “Ghost Stories” and “Dawning Delights” lore books.

Side bit: there’s a piece of lore where, after being revived and returning to her throne world, Savathûn is tracked down by Saint-14. He then proceeds to beat the crap out of her, not just for Osiris, but for himself.

AIAT was in front of you the entire time. Caiatl's name unknowingly comes from several Hive tales in the OXTA prediction engine that the Psions used. The OXTA prediction engine is assumed to be an anagram of Taox, the Queen Mother of the Osmium Dynasty. Essentially Calus named Caiatl after the star Caiatl, which was named from the reasoning that unlike all other stars in the system it shines the truest and does so undeniably (in reference to the "aiat" meaning of proof). A lot of Cabal rhetoric about war is derived from the ancient starfaring conquerers of the Hive but were transcribed potentially through the mortified lenses of Taox, who ended up betraying the Hive and siding with many enemies of the Hive to halt the genocide the Hive would create. This is also why you see Caiatl's best friends name as Umun'Arath in reverence of the conquerer's legacy... but this is also the same viral teachings that cause Umun's family to conjure Xivu'Arath onto Torobatl.

Taox might actually be our Hive ally, as Taox has yet to be found and has always escaped the reaches of the Hive. She also has several ties to the Vex who were seeking to integrate with the OXA machine, much like how Maya Sundaresh did during the Insight Terminus strike.

We're so close ! Please try to avoid any spoilers for final shape, there have been some crazy leaks today

Eris Morn, the Hive God of Vengeance

Immaru was actually part of Festival of the Lost a bit later in this season, along with Glint and Eido (and also Shaxx every so often). There's a lore book about him and Archie (the Exo dog) pulling off a candy heist.

Best Eris & Savathûn dialogue

The wish you're thinking about is Savathun's wish, the curse on the Dreaming City

AIAT!!!

This is my favorite season in lightfall

1:00:54 Ahsa's species is the uncorrupted version of the Worm Gods. It's also the same as the Leviathan

To clarify the wishes. Savathuns wish was the curse in the dreaming city which was put into effect when we killed riven. When Forsaken came out there were 15  secret wishes that could be put into the wall of wishes in the last wish raid. We only ever found 14 and the wish in Savathun's wings is the 15th

Around an hour in you were asking if Ahsa is similar in strength to a worm-god; this is actually answered in a lore tab from season of the deep, since it's from before things you have already seen not really a spoiler but I'll leave a tag for posterity;

Potential spoiler for those who have not finished season of the deep:














Ahsa IS a Worm god; or more accurately she is a proto-Worm God, the (as of yet unnamed) species that existed before the worm gods were changed. As the Krill are to the Hive, Ahsa is to the worm gods.
This was specified on the lore of a ghost shell cosmetic of all things (Bungie do like hiding their good lore), specifically the siochains-scuba-shell if you want to look up the actual lore tab on Ishtar collective.

Unless it's specified, like during the first mission of the Red War, Destiny time is always 1:1 with real time, the Witness has been inside the Traveler for more than a year by now

You might wanna read specific lore about Saint-14 during this season

The 'last wish' that Savathun had was for a curse to be unleashed on the dreaming city that cycles every 3 weeks. Also, season of the wish is the best seasonal story we've gotten, love the lore of the ahamkara

Just to clarify something with the wish, back in the Last Wish raid (Forsaken) there was a wall of wishes that gave small benefits.

In game there were 14 but 15 were in the files. People searched for months for the 15th wish and eventually gave up.

The wish is essentially them ending a 5 year old mystery