Warning spoilers for season 3 as some will be uncovered to avoid an all white page and these characters' history being tied to the events of the season.
The individuals whose actions proved instrumental in triggering the nuclear holocaust that destroyed the Earth 97 years prior and shaped the course of human history ever since, both on the ground and on the Ark. They appear in the episode Thirteen in the flashbacks.
Becca was a scientist and owner of Polaris, responsible for creating A.L.I.E. in the year 2051. Later she became the sole survivor of Polaris and descended to Earth to become the first Commander of the Grounders. The Commanders that come after her are also referred to as "Heirs of Bekka Pramheda" which indicates that she died. Moreover, it has been confirmed that there can only be a new Commander when the current has died.
- Alien Blood: She injected herself with a black fluid so that she can bond with the A.L.I.E. 2.0 and became the first official nightblood.
- Artificial Intelligence/ Cyborg: Becomes a cyborg when she turns her blood black and connects to the A.L.I.E 2.0 and an artificial intelligence when she eventually dies with her mind becoming apart of the chip along with the future commanders.
- The Atoner: She became obsessed with making up for the nuclear holocaust that her creation A.L.I.E. unleashed upon the world, which lead to the creation of the A.L.I.E 2.0.
- Back for the Finale: In the season finale as part of The Flame she is in the room where the kill switch is and gives Clarke directions to how to use it.
- Big Good: In the A.L.I.E. arc, due to the Flame chip being modeled after her psyche, allowing there to be something that can rival A.L.I.E. and the City of Light.
- Founder of the Kingdom: She was the First Commander of the Grounders and the architect of their civilization.
- Hot Scientist: One of the worlds foremost experts in artificial intelligence; she also happens to be drop-dead gorgeous.
- Non-Idle Rich: She was wealthy enough to own her own space station.
- Posthumous Character: She has been dead for decades at the time of the show. Her story is told through video recordings and flashbacks.
- Sole Survivor: As stated, she was the only survivor of the Polaris space station destruction as she fled to Earth.
- Unwitting Instigator of Doom: Her part in the creation of A.L.I.E lead to the destruction of Earth and her working on A.L.I.E 2.0 unintentionally lead to the destruction of the space station Polaris when the other stations found out about it.
- She's also the creator of the mind drives. They were intended to merely back-up someone's memories, to be viewed in case of death, but the Primes modified them to full-on Body Surf capacities, leading to Sanctum's culture being built around the worship of body snatchers.
A scientist and Beccas colleague, he helped with the creation of A.L.I.E.
- Driven to Suicide: His guilt over the nuclear holocaust leads him to shoot himself in the chest with a revolver.
- Early-Bird Cameo: The recordings of himself are seen by Murphy while he is trapped in the bunker at the end of season 2 and the beginning of 3.
- My God, What Have I Done?: He clearly considers the nuclear holocaust his fault, as it was his creation that unleashed it.
- Posthumous Character: He killed himself shortly after the nuclear holocaust, but left video recordings of himself.
- Unwitting Instigator of Doom: The creation of A.L.I.E leading to the nuclear holocaust.
The Commander of the Polaris space station.
- The Captain: After the nuclear holocaust he prioritizes the safety of the Ark over any loyalty to Becca, because the risk is too great.
- When You Coming Home, Dad?: He was unable to be with his wife and daughter as they died because he was on board Polaris during the nuclear holocaust.
- One-Shot Character: He is featured only in the flashbacks in the episode "Thirteen" as he has been dead for many years.
- Posthumous Character: He died 2 years after the end of the world when Alpha Station blew up Polaris as an example to solidify the other stations commitment to the Ark.
Gordon was Becca's lab assistant on the Polaris. She assisted Becca with the work on A.L.I.E. 2.0. Two years later, just before Polaris was to join The Ark, she informs Cole McAdams of their research. Gordon begs Becca to destroy her research, but Becca refuses, leading to the destruction of Polaris.