Ballas

Ballas is an Orokin Executor prior to the fall of the Orokin Empire. Suggested to be the lover of Margulis, whom he attempted to convince to destroy the Tenno for her own safety, an act which ultimately proved futile. He is also believed to be the Orokin primarily responsible for the development of Transference and the creation of the Warframes.

General
Much like Corrupted Vor, who proclaims that he is "energy", an immortal being incapable of death, Ballas and other high-ranking Orokin appear to be undying, as elaborated in the Fragments. It is currently unknown whether the process of Continuity - the transference of an Orokin mind into a new body - is the key to this immortality or not.

Fragments
Fragments recovered throughout the system also reveal Ballas' involvement in the creation of Cephalon Ordis, who he created from the mind of a mercenary warrior named Ordan Karris, bound to servitude with modified memories as punishment for the latter's attempt at killing him.

Synthesis
The Detron Crewman's Synthesis imprint also suggests that Ballas was involved with the creation of what would become the Sentients, a rather ironic action given that the Tenno would be created and deployed to fight the Sentients when they later turned on the Orokin.

The Second Dream
Dialogue during The Second Dream states that Ballas held the rank of Executor, and was implied to be romantically involved with the Archimedian Margulis. She had been protecting the survivors of the Zariman Ten Zero, whom she is later ordered to kill. Margulis refuses to kill them and is ultimately executed, with Ballas participating in the trial. After this Ballas would continue Margulis' work on Transference to develop the Warframes.

Apostasy Prologue
Ballas officially makes his first appearance in Apostasy Prologue, interrupting the Operator when they meet the Lotus in person. The Orokin apologizes in advance, which left the Lotus to question what he is sorry for, remarking that she is not his lover, Margulis. Ballas replies that she is merely imprisoned within before waving his hand, releasing an energy wave that disconnects the Lotus from her own pod.

"Ballas?"

- Lotus

This causes the Operator to wince in pain, distorting the player's screen in a similar fashion to The Second Dream. The Lotus then seems briefly surprised and then appears to recognize Ballas, calling out his name. He vows never to abandon her again while offering his hand. The Lotus, no longer protesting Ballas' claim that she is Margulis, takes off her mask before taking his hand. The two then walk together into a blinding light in front of the Tenno before disappearing.

The Sacrifice
Ballas makes his second appearance in the Sacrifice during which it is revealed he is indeed responsible for the creation of Helminth and Warframes having created them from individuals infected with a unique strain of the Infestation. The goal was originally to use them as-is, mindless drones under Orokin control, but this failed with the Warframes quickly going feral and becoming uncontrollable.

During the quest through the memories of Excalibur Umbra and the Vitruvian relic it is revealed that it was Ballas that revealed the weakness of the Tenno and their Warframes to Hunhow as part of a deal betraying the entire Orokin empire and defecting to the Sentient.

At the climax of the quest, Umbra managed to defeat Ballas with the assistance of the Operator, suffering a stab to his abdomen. Slumped onto the ground, unconscious, Lotus, in the form of Natah arrived as reinforcements and rescued Ballas.

Trivia

 * So far, Ballas has been the narrator of the newest line of Prime introduction videos/trailers.
 * In Saryn Prime's introduction video, his dialogue indicates that he developed Saryn as a means to fight the Infestation, as well as that her design may have been inspired by Margulis' love for the natural environments of Old Earth.
 * In the Vauban Prime trailer, it is indicated Vauban was created to fight the Corpus. The narration also implies that the ancestors of the current Corpus faction were active during Orokin times and that they may have had a hostile relationship with the Orokin, at least sometimes.
 * In Nekros Prime's intro video, Ballas seems to directly address his fellow high-ranking Orokin, stating, "Your graces, we who are beyond death, have forgotten the simple power of fear."
 * In the video for Banshee Prime, it is indicated that Prime Warframes, if not Warframes in general, were made to create a set of units who are much more unique and capable than the mass-produced and decrepit Grineer.
 * In Valkyr Prime's intro video, Ballas mourns the loss of animalistic aspects the Orokin tossed away for their immortality and beauty. Because of this, he warns that the Warframes themselves are to be feared even though they are Tenno controlled. That they're merely biding their time as they wait to strike at their Tenno and Orokin masters.
 * Thus far, this is the only trailer to not mention the name of the Warframe being showcased.
 * In Oberon Prime's preview video, Ballas talks about the errors of greed, as the greedy do not think of the consequences, evident with the Grineer who often plunder the forests of Earth. Thus, Ballas talks of Oberon as the avenger of the forest, the one who will place judgment on the Grineer who have contaminated the greenery for too long. And through the blood of these defilers will the forest grow stronger.
 * In Mirage Prime's video, Ballas recognizes the suffering that the Tenno--or perhaps of the beings/lifeforms from which the original Warframes themselves were developed--endured to become what they are. He states that Mirage "played the fool" while others "writhed and raged in the vice," echoing some imagery from the scenes of Alad V's torturous vivisection and experimentation on Warframes he had captured. Mirage's tricks allowed her to "distort [Ballas'] design."
 * The introduction ends with Ballas stating no one is laughing anymore except Mirage. At the very least, this line suggests Mirage proved to be an effective killer, the only one left laughing on the battlefield. The phrasing may also allude to greater significance relating to the Tenno/Warframe betrayal Ballas warns of in Valkyr's introduction.