Ahsa

Ahsa is an enormous serpentine creature living in the methane ocean of Titan.

Biography
According to memories Ahsa shared with Deputy Commander Sloane, Ahsa is a member of the species that gave rise to the Worm Gods, in the same way that the Krill gave rise to the Hive. She and others of her species lived on Fundament, where they led a peaceful existence. However, at some point her people became seduced by the Witness' philosophy, and began attacking and killing one another in order to achieve ascendancy through the Sword Logic. Ahsa escaped the bloodbath and fled into space, pursuing the distant Traveler as it made its way across the universe. At some point following her escape, she learned of the Witness' origins and motivations from an unknown source.

At another point in history, Ahsa had tried to prevent the Hive from discovering other Worms, though how and where she did this is unknown. This is noted to be the reason for which Xivu Arath hunts Ahsa.

Billions of years later, Ahsa's travels led her to the Sol System, where she crashed into Titan and hid within its methane seas.

The Golden Age
Records of Ahsa's existence on Titan date back to the Golden Age; her presence registered on subsurface scanning equipment, and she was a subject of study for several marine biologists stationed on Titan, who designated the creature as "TLev-01" in their reports. According to archival data accessed by Síocháin, the Ghost of Deputy Commander Sloane, Ahsa had been discovered by researchers to be intelligent and evidently capable of telepathy, and had attempted to communicate with several research station personnel, including Gideon Tepin.

The Collapse
During the Collapse, Ahsa was attacked by Nezarec, but survived the encounter. At some point during the Collapse, she also lost an individual whom she had become psychically bonded with.

Red War
During the missions Utopia and Ace in the Hole, a massive serpentine shadow can be seen on the windows surrounding the New Pacific Arcology's CPU core in the Festering Halls, presumably cast by Ahsa. The Ghost also mentions that the Arcology's sensors can detect a large object moving underneath The Rig, likely the same creature. Sloane can also be overheard in Siren's Watch talking about something below the waves, claiming that it wasn't her imagination. Guardians have also observed serpentine, finned creatures breaching the surface of Titan's oceans, which are likely Ahsa or other life-forms native to Titan.

During the Arrival of the Black Fleet, the Drifter makes reference to "the long boy in the soup" when speaking to Eris Morn, likely referring to Ahsa, mistaking the creature's gender.

Contacting the Lightbearers
After Titan was Taken by the Witness, Ahsa attempted to establish contact with Sloane, who had fallen into the methane ocean. She later came to Sloane's rescue when the Titan and her Ghost were about to be killed by a Knight of Xivu Arath.

On Neomuna upon repairing all of the Cloud Strider monuments, a submind of Soteria sends a message to the Guardian, informing them that an "enemy of the Witness" is hiding on Titan, indirectly referencing Ahsa. After Titan reappeared and Sloane re-established contact with the Vanguard, the Guardian and the Drifter worked together to strengthen Sloane's psychic connection to Ahsa using coralized Egregore harvested from the depths of the methane ocean. In doing so, they hoped that Ahsa might be able to communicate vital information about the Witness to Sloane. Over the following weeks, Ahsa would use her egregore-reinforced connection with Sloane to impart messages to her using the Darkness, which Sloane relayed to the Guardian. The content of these messages, though cryptic and difficult to interpret, seemed to refer to events surrounding the Witness' origin. These sessions culminated in Ahsa's and Sloane's minds briefly becoming one, allowing Ahsa to communicate more clearly and relate the story of the Witness' origin to the Guardian.

One week later, Ahsa was taken captive by Xivu Arath's forces, who attempted to convert her into a Taken using a ritual. Through a combined effort by Sloane, Zavala, Saint-14, Saladin Forge, the Drifter and the Guardian, the ritual was stopped and Ahsa was rescued.

Following this, Ahsa returned to the Arcology and communed with Sloane a final time. Xivu Arath attempted to interfere, briefly taking over Sloane's body through her Taken corruption, but Sloane managed to regain control and re-established her link to Ahsa, who spoke through Sloane to tell the Guardian that they must enlist the aid of Savathûn in order to follow the Witness through the portal on the Traveler. Exhausted by the effort of her repeated communions, Ahsa then entered a state of hibernation in order to recover her strength.

Ahsa's messages
The following are transcripts of Ahsa's messages to the Guardian, relayed through Sloane:
 * An oasis in the desert. Seeds of hope... buried beneath the sands... Nomads... wanderers... travelers. Their journey comes to an end... The first to be claimed by the Deep... [breathes uneasily] the first to fall victim to the Witness...
 * A city of Light... a... a flourishing garden... A silent god... withholds a deeper truth. Questions unanswered, uh... longing unfulfilled. The sky... darkens... as a new journey begins.
 * Shrouded in... Darkness. A promise of something more... Two halves of a whole... long divided. A schism between them. Reunited. [exhales in joy] A glimpse beyond... to the beginning...
 * Anathema... calamity! That which cannot, MUST not, come to pass... A wordless denial. A fleeing god. Betrayal... and escape. The pursuit... for the final shape... 
 * Our minds are one, linked by the Darkness. But only for a moment. I must borrow Sloane's voice to speak my words. Please... heed them well. Before you can confront the Witness... you must understand it. The Witness's first victims were once like you. Struggling for survival. Bolstered by hope... Until their hopes became reality. They called it "the Gardener," their deity of life. It ushered them into a golden age. For eons, they prospered. But their newfound god never spoke to them. It lavished them with gifts, but not with guidance. And though they lived in paradise, they came to crave a greater purpose. They desired meaning. Structure. A "Winnower"... to shape the garden. Their scholars discovered that the Gardener shared a connection with another entity among the stars. They called it "the Veil." And when they found it, they arrived to claim it. They already knew much about the Light. How it could bend the laws of the universe and create life. But they came to realize it could bring ruin... just as easily. The cosmic event it set in motion could wipe out entire civilizations in a heartbeat... without reason. And so they saw the Light not as a source of prosperity... but of unfettered chaos. By studying the Veil, they came to know the Darkness. A power that was shaped by thought and consciousness. And in the Darkness, they found the means to carve away the chaos of existence. To calcify it into a final shape. Eternal... and perfected. They brought the Veil back to the Gardener in an attempt to strengthen their connection. There, they could reshape reality itself. The Gardener would not allow it. And so, it fled their world. But they would not be deterred. Having witnessed the truth in the Darkness, they used its binding power to merge themselves...into the salvation they craved. Thus began the Witness's pursuit... its campaign to impose meaning on a meaningless universe. One that is nearly at its end.
 * The true path lies obscured. But she knows the way. She who hides truth... in deception. The Witch Queen... must rise.

Trivia

 * Before Titan was moved to the Destiny Content Vault, if one went beyond the normally player-accessible areas of Titan and managed to see below the surface of the ocean, they could see . These were seemingly intended to be the dorsal fins of Ahsa breaching the waves, as normally only the uppermost part of the wheels would be visible.
 * However, these same fins can also be seen in Savathûn's Throne World.

List of appearances

 * Destiny 2
 * Season of Arrivals
 * Lightfall
 * Season of the Deep
 * Season of the Witch