Ordis

Ordis is the AI - also referred to as a "Cephalon" - of Orokin origin on board the Liset. He manages the various systems on the ship, as well as assisting the Tenno, whom he refers to as "Operators", in providing information in between missions. New players will first encounter him during the introductory quest, Vor's Prize.

General
Ordis is programmed to assist the Tenno and although he remains mostly functional, damage from the Grineer's salvaging operations has left him without any memory of the Old War. In addition, both the damage and abandonment has resulted in periodic bursts of anger during conversations (in sharp contrast to the calm tone of voice used by other cephalons), occasionally correcting himself shortly afterwards.

Vor's Prize
After Captain Vor shoots down the Liset sent in to rescue the newly awakened Tenno, the Tenno encounters another Liset (with Ordis onboard) impounded nearby. Ordis initially mistakes the Tenno for another Grineer soldier, but soon realizes their true identity and helps them escape.

As the Tenno is being familiarized with their surroundings, the Lotus instructs the Tenno to retrieve replacement components to restore the Liset's functions (to Ordis' delight, as this allows the Tenno to exact revenge on the Grineer and the Corpus for gutting him of his components). Along the way, the Tenno rescue a black market merchant named Darvo, who -while willing to help the Tenno remove the Ascaris implanted by Vor- gets into a small squabble with Ordis due to Darvo's former ties with the Corpus.

Howl of the Kubrow
Upon hearing news of the Tenno's desire to obtain a Kubrow, Ordis makes his distaste for them clear, viewing them as smelly, unhygienic creatures that threaten to soil the pristine interior of his ship. Over time however Ordis becomes more accepting of the newly hatched Kubrow commenting that its barking and panting are "not displeasing".

The Limbo Theorem
Upon analyzing the titular theorem, Ordis initially dismisses it due to its incomplete nature. However he notices that the theorem points to a faint tuning frequency, which can only be picked up by space-borne Grineer communications towers stationed on Mars.

Ordis directs the Tenno to collect proof fragments in order to complete the Theorem, but is initially annoyed that it still remains complete gibberish, save for a coordinate that leads to Earth. The Tenno begin excavating the area, and ultimately discover a component for a newly discovered warframe. Once the Tenno construct it, Ordis discovers new information that begins to unravel the theorem's message, piquing his curiosity. As he goes through the theorem, Ordis discovers that the warframe the ability to access a plane of reality between the normal plane and the Void. Ordis directs the Tenno to another coordinate on Europa to retrieve another component, eagerly awaiting new discoveries.

Once the Tenno uncover another component, Ordis reveals that the Theorem also doubles as Limbo's biography, having written it purely in math. Once the second component is built, Ordis points out one last coordinate on Phobos in order to find Limbo's last component. Once the final component is obtained and built, Ordis eagerly reads through the next part of the theorem, only to discover that it was Limbo's last equation, having killed himself due to a miscalculation while accessing the Rift (Ordis offhandedly mentions that there is a good reason why his components are so widely dispersed).

Dejected, Ordis reminds the Tenno to exercise more caution once they get Limbo for their own use.

Stolen Dreams
As the Tenno retrieve portions of the Arcane Codex under Maroo's direction, Ordis suggests that the Codex may lead to an Orokin treasure (to his and Maroo's delight), and is shocked that the Codex was written by another Operator. Once the Tenno complete the Codex, Ordis comments that any machine that could possibly read the Codex is long gone, only for Maroo to point out that she obtained the Codex from a machine deep in an Orokin Derelict. Ordis theorizes that the machine could read the Codex, and the Lotus instructs the Tenno to head to Phobos (where a portal leading to said derelict is located) in order to decipher the Codex.

Once the Tenno find the machine and insert the Codex, it broadcasts a cryptic message before the machine vanishes. Disappointed that there is nothing of value, Ordis apologizes to Maroo for getting her hopes up (in spite of her misnaming him "Ordo" throughout the search) before she parts ways with the Tenno.

The New Strange
While the Tenno investigate information regarding a warframe long thought dead, Cephalon Simaris notices Ordis and reveals that the latter is a still-functional Series 2 Cephalon; all other cephalons of that make have since degraded beyond repair. Throughout the Quest Ordis is taught by Simaris on how to decipher the various transmissions and codes required to solve the mystery they are hunting down. Impressed with his abilities, Simaris offers Ordis a chance to be the steward of his Sanctuary, while also promising to restore Ordis back to full functionality, as he believes that Ordis is squandering his potential manning the Liset.

When the time to defeat Chroma arrives however, Ordis with his newfound knowledge suggests synthesis versus destroying it, going against Simaris' wishes. Ultimately, Ordis turns down Simaris' offer, stating that he is foremost the Operator's Cephalon.

Trivia

 * The word Cephalon derives from the Greek κεφαλή (cephale), meaning "head".
 * While Ordis is not explicitly mentioned as an Orokin AI, the Liset used by the player is referred to by Lotus as an Orokin Ship, thus leading to the assumption that Ordis is of Orokin origin as well.
 * Ordis' occasional outbursts of uncharacteristic emotion could be attributed to damage to the AI or to the ship itself; supported by the visible damage to the cube in its portrait, as well as its frequent glitching and comments on itself needing maintenance. This damage was likely caused by the Grineer as they gutted the Liset of all but its basic functions.
 * Ordis' cephalon model is of "Series-2", according to Cephalon Simaris, who consideres it an antique, reinforcing the belief of Ordis' Orokin origin.
 * A part of the Series-2 programming likely involves suppression of self-aware expressions straight-forwardly put to the Operator. During The New Strange questline, Ordis attempts to refer to himself in 1st person, taking Simaris, the much more advanced Cephalon, as an example. This causes a glitch and he reverts to 3rd person reference. Given his Orokin origin, the likely cause is that earlier Cephalons were more intended as "servants" and using "I am" expressions would imply heightened level of individuality.