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, Ahsa returned to Fundament, perhaps in her pursuit of the Traveler; Sloane mentions that Ahsa had tried to prevent the Krill from discovering the Worm Gods, though her role during this period is unknown.[1]
Billions of years later, Ahsa's travels led her to the Sol System, where she crashed into Titan and hid within its methane seas.[2]
The Golden Age
Season of the Deep Spoilers
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. [3]
The Collapse
Season of the Deep Spoilers
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.[4]
Red War
During the missions Utopia and Ace in the Hole, Ahsa's shadow can be seen on the windows surrounding the New Pacific Arcology's CPU core in the Festering Halls. 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 Season of Arrivals, 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.
Season of the Deep
Season of the Deep Spoilers
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.
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 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.
Ahsa's messages
Season of the Deep Spoilers
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... the first to fall victim to the Witness...
A city of Light... a flourishing garden... a silent god withholds a deeper truth... questions unanswered... 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... 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... [5]
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 massive finned wheel-shaped objects. 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.