Aletheia is an Isu and the Dikastes of Atlantis around the time of the Human-Isu War. Unlike many of the known Isu who were deified by their human slave species, Aletheia became a personification of truth and was repulsed by those among her own people who had embraced divine status.
When Aletheia later suffered a grave injury, Loki, desperate to save his lover, transferred her consciousness into a Staff of Eden. From there, she would one day interact with the Keeper of the staff and help the Staff's heir in her journey. She also made numerous recordings on the Olympos Project and stored them in the Gateway to the Lost City, a vault connected to Atlantis. In order to teach Kassandra how to use the staff, Aletheia also created several simulations based on the memories of her time as Dikastes of Atlantis.
Aletheia was considered a god in Greek mythology. She was also known by her Roman counterpart Veritas.  The Norse name for Aletheia was Angrboða, considered among one of the jötnar in Norse mythology. Her name of Angrboða could roughly be translated into "the one who brings grief," "she who offers sorrow," or "harm-bidder", while other sources translated it as "truth-giver."
Dikastes of Atlantis
During the Isu Era, Aletheia served, for a time, as the Dikastes of Atlantis, appointed by the city's ruler Poseidon. During her tenure, she attempted to bring balance by passing judgement on the city's laws and customs. At one point, Aletheia became aware of the Olympos Project, a scientific exercise conducted by her fellow Isu Aita and Juno as a means to quell a rebellion by the humans if they ever revolted. Horrified at their experiments, Aletheia made numerous recordings detailing their actions and stored them in a number of steles in a vault connected to Atlantis.
In time, she also became acquainted with Hermes Trismegistus, and after she was fatally wounded and Loki wanting to save his lover transferred her consciousness into Hermes' own Staff, so that she could interact with and help the wielder of the staff, known as the Keeper, to control its power in the future beyond her time.
Helping the Keeper
Around 422 BCE, a projection of Aletheia summoned the Spartan misthios Kassandra, now the owner of the Staff of Hermes Trismegistus, to the Island of Triton. There, Aletheia introduced herself to Kassandra, asking her to pledge herself as the "Heir of Memories". She then told Kassandra to find Theras, in order for the Heir to continue her journey.
Aiding the Heir of Memories
After finding Theras, Kassandra was sent to find three tombs. Aletheia appeared at the entrance of each, in order that Layla, acting as the Heir of Memories, would be able to unlock the gate to Atlantis. During Layla's exploration of three tombs, Aletheia revealed that she had a consciousness kept within the Staff, able to communicate with Layla and listen to frequencies, speaking of a currently unidentified male "interloper" who was interfering with the communications frequency between the Altair II and Layla.
After the gate to Atlantis was unlocked, Aletheia appeared as a projection to Layla, and later to Victoria Bibeau, instructing that Layla synchronise with Kassandra's experience of Aletheia's custom built simulations in order to unlock the full potential of the Staff of Hermes Trismegistus.
Aletheia eventually resurfaced to let Laya continue with the trials until Victoria interrupted, fearing for Layla's destabilizing vitals. Aletheia witnessed a Bleeding Effect-crazed Layla strike Victoria dead with the Staff's power, to which caused her to regret choosing Layla as the Heir of Memories.
Aletheia reluctantly agreed to let Layla conclude the final trial, but followed her into the simulation supervise her actions. Upon completion, Alethiea returned Kassandra from the simulation and congratulated her. Aletheia then spoke out to Laya one final time and warned her that the interloper, revealed to be Juhani Otso Berg, had reached their location before fading away with the Animus transmission.
In 2018, Layla Hassan kept a record of her findings about Aletheia on her laptop.
Behind the scenes
According to Pindar's Olympian Ode, Aletheia was the daughter of Zeus, however according to Aesop's Fables, she was crafted by Prometheus. Aletheia was also revered as the Greek goddess of truth, as was her Roman equivalent Veritas. Aletheia, ἀλήθεια, is Greek for 'not a lie, truth'.
- Assassin's Creed: Odyssey (first appearance)
- Assassin's Creed: Valhalla (as Angrboda)
- Assassin's Creed: Odyssey – Layla Hassan's personal files: "Who is Aletheia"
- Assassin's Creed: Valhalla – Animus Anomalies
- Assassin's Creed: Valhalla – Database: Angrboda
- Assassin's Creed: Odyssey – The Fate of Atlantis: Judgment of Atlantis – The Fate of Atlantis
- Assassin's Creed: Odyssey – The Gates of Atlantis
- Assassin's Creed: Odyssey – The Heir of Memories
- Assassin's Creed: Valhalla – Animus Anomalies
- Assassin's Creed: Odyssey – Modern day
- Assassin's Creed: Odyssey – Memories Awoken
- Assassin's Creed: Valhalla – Modern day
- Veritas on Wikipedia