Beast King GoLion
Sincline's mother only appears in Sincline's nightmares and Honerva's flashback, mostly featured in Episode 30.
In Sincline's bad dreams, he sees his own mother calling out his name in the middle of a dark environment. Whe he tries to reach for her he sees her being strangled and ultimately pulled away by demonic hands that resembles those of his father. Sincline states that these dreams are recurring and he sees Fala's face in place of his mother's. This is to show that Fala bears a striking resemblance to his mother, and that Sincline's obsession with Fala is rooted in an oedipal complex.
Information about his mother is withheld from Sincline by both Daibazaal and Honerva, in order to prevent Sincline from realizing his Altean heritage; instead, they tell him that she died when he was born, but he refuses to believe it. At some point Honerva confided with Sincline to confirm that his mother did resemble Fala, but refused to reveal her Altean origin and fate.
In a flashback coming from Honerva's memories, the whole deal is revealed. It's shown that Sincline's mother, an Altean woman who was Daibazaal's concubine, tearfully attempted to beg Daibazaal to spare the lives of other captives despite him telling her that he wouldn't budge even if she, the mother of his son, pleaded with him. She was murdered by him for not only opposing his stance despite her position, but by defiantly telling him to kill her with them if he won't spare them.
Sincline doesn't officially learn the whole story about his mother until the very end of the series, from Honerva's own mouth and after he has sent Daibazaal to his own death. When this happens, the already unstable Sincline goes absolutely insane and viciously stabs Honerva to death.
- In the non-canon crossover, Robotech/Voltron, the character Lora is an homage to Sincline's mother and appears in Lotor's memories. She is explicitly said to be Zarkon's Royal Consort, looks exactly like the character she was based from, and her fate in the comic is much like her fate in Beast King GoLion: she is killed by Zarkon for begging him to stop taking innocent Arusian lives, when Lotor is just a small child.
- In Voltron: Defender of the Universe, all scenes depicting Sincline's mother were localized into Lotor dreaming about Allura at a more mature looking age.
- Curiously, the exact scene depicting Sincline's mother's death is not cut out of Voltron: Defender of the Universe, but rather has its dialogues changed to change the circumstances.