TL;DR: I believe that Rasputin has been somehow captured by the Warmind Charlemagne on Mars, that the Hunter Ana Bray is somehow investigating this or is involved, that the next Destiny expansion Gods of Mars will revolve around these two things, and given that the Golden Age corporation Clovis Bray developed SIVA, we may be in for a wild ride!

In Destiny 2, one of the best new additions to the game are the short, open world based “Adventure” missions. These missions often pull you across a Destination’s Patrol zone while sprinkling in fun bits of story here and there.

Sometimes adventures are fairly instances off affairs, like the one in the EDZ where you transmat a bunch of Fallen explosives to the top of the mountain then lure a bunch of Cabal right into them. Other times, they are awesomely openly multiplayer, like the one where you have Failsafe interface with Nessus only to have to battle the Vex to get her back. A big part of that one occurs around the edges of a Public Event zone, and when both occur at the same time it gives the overwhelmingly hectic Destiny 1 Skywatch a run for its money.

But one of the neatest, perhaps most overlooked things that Bungie did with Adventures is hide preludes to each of the first two Destiny 2 expansions with in them. For Curse of Osiris, there’s the one Adventure where you scan Vex structures high up above the Nessus forest. At the end, your Ghost lets you know that it had some unexpected help from within the Vex systems. And that the one who provided this help signed off as “Osiris.”

Similar to this, I believe two of the Adventures on Io are pointing towards the rumored Gods of Mars expansion.

The first, Road Rage. Early on in the mission your Ghost and Asher Mir have this exchange:

Ghost: What kind of information do the Vex want from the Warmind Vault?

Asher: The Warminds had a special connection to humanities lost arts. Music, literature, film. The Vex may not understand this emotional frivolity, but they will use it as a weapon against us. If we let them.

This is the first real mention of Warminds being more than military devices. We know the Exodus Red referred to a Warmind, probably Rasputin, as “The Tyrant.” We know that Rasputin, and perhaps the other Warminds, were preparing Humanity in case something bad came out of the same nowhere that the Traveler did. We also know that Warminds were in some way on-call by researchers of the Ishtar Collective on Venus as they studied the Vex ruins there, and later in charge of Maya Sundaresh (who I believe to be the Exo Stranger)and her team on Earth as they pieced together some sort of mind displacement (time travel?) device.

But all these Golden Age references paint the Warminds in a military light. That they are or were repositories of Humanity’s art and culture is a new, Destiny 2 concept. But it could easily make sense. It wouldn’t be the first time a Bungie AI had such a connection to Humanity:

Forerunner Monitor “343 Guilty Spark”, the caretaker of Halo 04: Ridiculous! That you would imbue a warship's AI with such a wealth of knowledge! Weren't you worried it might be captured? Or destroyed?

During the Road Rage Adventure, you are tasked with killing Vex to recover the data they have been stealing from Io’s dead(?) Warmind. After you destroy the last Hydra, your Ghost chimes in with:

We got him, Asher. Looks like the Vex did steal files from the Vault. Let's see... Some files about Mars, somebody named Ana Bray... And of course lots of data on the Warmind Project. Hmm. You'll have to take a look. I hope it's useful.

Ana Bray? Interesting...

In the Adventure “Arecibo”, your Ghost detects an odd series of transmissions spread across Io. As you home in on each transmission, you find strange rotating objects, kinda like two pyramids stacked on top of one another. Each one is playing “ancient” earth music, and each has an odd quote embedded within a sub channel or some such thing.

The first of these strange beacons is playing some very old sounding music whose identity I could not suss out. It is possibly Japanese since the accompanying quote is:

Real things in the darkness seem no realer than dreams.

This is a quote from the 11th Century Japanese text, the Tale of Genji by Murasaki Shikibu. Wikipedia tells us that:

The work recounts the life of Hikaru Genji, or "Shining Genji", the son of an ancient Japanese emperor, known to readers as Emperor Kiritsubo, and a low-ranking concubine called Lady Kiritsubo. For political reasons, the emperor removes Genji from the line of succession, demoting him to a commoner by giving him the surname Minamoto, and he pursues a career as an imperial officer. The tale concentrates on Genji's romantic life and describes the customs of the aristocratic society of the time.

Our Ghost tells us:

So it turns out, both the music and the quotation, predate the Traveler's arrival in this solar system. They're old. Maybe we activated some kind of high-tech time capsule."

The 2nd beacon is playing “Music for the Royal Firework: Overture.” This particular example was recorded by Gregor Narholz.

Wikipedia has this to say about Music for the Royal Firework:

The Music for the Royal Fireworks (HWV 351) is a wind band suite composed by George Frideric Handel in 1749 under contract of George II of Great Britain for the fireworks in London's Green Park on 27 April 1749. It was to celebrate the end of the War of the Austrian Succession and the signing of the Treaty of Aix-la-Chapelle (Aachen) in 1748.

The encrypted quote going along with this beacon says:

Misdirected by accident or intent, intelligence can foster it's own ecstasies of growth and decay.

It is actually a paraphrase of a statement by Octavia Butler in her 1993 environmental dystopia SciFi book The Parable of the Sower. That book focuses on a woman who is forced into a cruel dystopian world after society collapses in the 2020’s. This woman eventually forms a new community who believes that it is Humanity’s destiny to someday spread to other planets.

After scanning this beacon, our Ghost says:

The wierd thing is this audio file was just updated. So... this can't be a time capsule. Someone's trying to talk to us. No, no. Some thing. This has to be an AI, right? An old *Golden Age AI. Like Failsafe...

The third beacon is playing a song called the Pipal Tree Romance. This article from Quora tells a bit about the significant of trees and the Pipal tree to Hindu culture:

Trees are sacred in India, and often associated with a god or a goddess. Some scholars believe that it is the tree that was worshipped first, maybe for its medicinal or symbolic purpose, and that the gods and goddesses came later. That may be the case but today trees are an integral part of a deity’s symbolism.

The Peepal tree is associated with Yama, the god of death and the tree is often planted outside the village near crematoriums.

The Peepal tree does not let a blade of grass grow under it. Thus Peepal tree does not allow for any rebirth and renewal. While Peepal offers shade from the sun, it offers no food. That is why it is not part of fertility ceremonies like marriage and childbirth where food-giving, rapidly renewing, plants with short lifespan such as Banana, Mango, Coconut, Betel, Rice and even grass, are included.

Thus, it emerges that in Indian thought, there are two types of sacredness – one that is associated with impermanent material reality and the other which is associated with permanent spiritual reality. The Banana and the Coconut fit into the previous category; the Peepal fits into the latter. Banana is the symbol of the flesh, constantly dying and renewing itself. Peepal is the soul – never dying, never renewing itself.

The quote that goes along with this music is:

Once war has been undertaken, no peace is made by pretending there is no war.

This is a quote from a Sanskrit poem that is important to Hinduism. Again, from the Quora article:

Mahabharata tells the story of a woman called Savitri who lost her husband as destined, one year after her marriage, near a Peepal tree. She followed Yama to the land of the dead and through determination and intelligence managed to secure back her husband’s life. In memory of that event, Hindu women go around the Peepal tree, tying seven strings around it. This is imitative magic: by symbolically going around the immortal tree, the women are binding immortality into their married life. They are securing the lives of their husband, the pillar of their household. They are protecting themselves from widowhood which is believed by most Hindus to be the worst fate for a woman.

Our Ghost concludes:

What does that mean 'by pretending there is no war?' I'm not sure I like the new guy.

From here we proceed down into Warmind Vault JYS-2 where a bunch of Vex transmat in but are repeatedly frozen by each of these songs as we clear them out. As we enter the Vault our Ghost says:

Someone must be expecting us. Is anyone here? Rasputin?

And:

You know I'm going to be really disappointed if this is all just an elaborate trap to kill us.

In this Vault are a few scannable objects:

Ghost: "The Warmind Network used to span across the entire solar system. I guess during the Collapse, it just... fragmented." - IO-JYS-1

Ghost: "Looks like this thing used to store files. Someone by the name of Bray scrubbed the data." - IO-JYS-2 (This one happens when you scan what looks like a discarded music beacon off in a dark corner.)

Ghost: "Ikora liked to say the Warminds were our only real link to Earth's history. Life with the Traveler, during the Golden Age. Pre Collapse." - IO-JYS-3

With that battle complete, our Ghost notes:

Weaponised music... Creepy quotations... All signs point to Rasputin, but. I don't understand how he could be here.

Our Ghost not understanding links back to an exchange with Ikora earlier during your time on Io during one of the storyline missions:

Ghost: So, uh… are we going to see Rasputin? Or is this some other Warmind?
Ikora: There is only one Warmind, but Rasputin is not here on Io. I believe he has been marooned on Earth ever since his network fragmented.

The fragmenting Ikora is talking about is probably the widespread disruption and destruction caused by Oryx during the Taken War… with perhaps more of the same caused by Ghaul as his Red Legion invaded the solar system.

What Ikora is saying here is that no, the Warmind we poke around in on Io was not Rasputin. Maybe its possible to guess which Warmind it was by the JYS designation of its bunker? What she is also saying is that Rasputin has been even more out of contact than normal (even in the Golden Age he was known as the Tacit King) and that she believes that he has been cut off from most of the Warmind network once more. She thinks he is stranded on Earth. Possibly in the Cosomdrome?

What happens next, though, seems to shed some light on what actually happened to Rasputin. We open a strange panel deep within the dead Warmind to find a bunch of those music beacons. One of them activates and our Ghost says:

Ah, that music... it hurts... just... give me a second... It says... 'Never ask for anything! Never for anything, and especially from those who are stronger than you. They'll make the offer themselves, and give everything themselves.'

This is a quote from The Master and Margarita by russian writer Mikhail Bulgakov. Wikipedia says:

The story concerns a visit by the devil to the officially atheistic Soviet Union.

Lots of bad thing happen in this story, but in the end “Because the Master and Margarita did not lose their faith in humanity, they are granted "peace" but are denied "light" — that is, they will spend eternity together in a shadowy yet pleasant region similar to Dante's depiction of Limbo.”

After our Ghost tells us the quote, he then says, in an increasingly distressed / altered voice:

I don’t understand. Wait. Something’s happening… Gah! Red Sand! Mars! Ice Caps! Ahhhhh!

As noted on Destinypedia the music that plays during this moment is Tchaikovsky's 6th Symphony, First Movement. This is the music that Rasputin’s plays all throughout Destiny 1, most notably as Omnigul spawns in waves of enemies to fight you during the Siege of the Warmind mission in The Dark Below expansion.

So… is it Rasputin who has been sending these strange musical messages? Maybe! Almost certainly the last one is a distress signal. But, it should be noted that the rumored plot of the Gods of War expansion is that Charlemagne, a Warmind whose name we first spotted way back pre-Destiny 1.

Destinypedia again save the day with the exact references:

Charlemagne would have appeared in the original story of Destiny, and was mentioned in pre-alpha marketing material, which claimed players were to retrieve a shard of its core intelligence, but was never mentioned in the final version of the game itself.

A location in the Dust Palace called "Charlemagne's Vault" was also supposed to appear in the game and serve as the place where the player obtained Thorn, but this was also removed or never completed.

The only possible surviving reference to Charlemagne is Ghost commenting that the Dust Palace once housed "the Warmind of Mars", but this Warmind is never identified by name.

The Arecibo mission finishes with our Ghost saying:

Hey! Sorry, I spaced out for a second there. What were we doing?

This clearly indicates that this was some sort of brief hostile takeover, and not part of the music we were hearing.

So what’s going on here? I’m still pondering everything and trying to look into the quotes a bit more as I have time, but here’s what I think / hope:

1. Ana Bray a Hunter who was around as recently as Twilight Gap and who share a name with the Bray family who ran the Clovis Bray advanced research and technology corporation on Mars might be poking around Mars. Specifically in regards to Charlemagne and Rasputin.

We don’t know a lot else about Ana Bray except:

She was at Twilight Gap:

You want another story about the Twlight Gap? Ana Bray, the Hunter. We all dug deep that day. We all touched the Light in ways we never thought we could. Or should. Ana, though. When she fired the Gun, where her Golden blasts hit home, she left behind the pools of light. Like splashes of sunlight that burned and burned." —Lord Shaxx

And she has a ongoing journal in that important looking room near the entrance to the new Tower’s hanger:

Looks like a journal: Ana Bray. But I can't tell who— Pretty much the entire thing is redacted. And there are whole pages missing. Something about all this seems… wrong. Am I worrying too much?

And she has been poking around on Io recently?

2. Rasputin is in distress somewhere on Mars. Probably near one of the Martian ice caps. Rampant Speculation says that maybe he’s been captured by a reawoken Warmind named Charlemagne.

3. This all links back to my early speculation about the Gods of Mars. Embarrassingly, I missed a member of the Bray family from that list. There was also Elise Bray, who helped developed the jump ship Eon Trespass.

P.S. In the future I hope to look into possible links between the various pieces of music and their associated quotes. But not now. This thing is long enough already!