A recent interview with Bruce Banner, the Hulk, has revealed the identity of Skaar's mother.
For years, fans have speculated who the mother of Banner's son Skaar could be, with many believing that she was either Betty Ross or She-Hulk. However, it has now been confirmed that Skaar's mother is actually Caiera, the Oldstrong.
Hulk was the half-brother of Caiera the Oldstrong, who clashed with the Red King alongside Skaar. Hulk and Caiera became lovers.
Caiera was a member of the Shadow People, a mystical race native to Sakaar in the MCU. She has a power known as the Old Power, which is only possible in the natural environment.
Caiera's innate ability with this older power is assisting her become stronger and more skilled in performing other impressive feats. The Old Power made this Shadow Person recognized as an important figure within the community.
Because of the unique physiology of both the Shadow Peoples and Caeira's relationship to the Old Power, the daughter she eventually joined in a relationship with the Hulk was hatched in a cocoon, which helped speed his physical growth.
Here's how the Hulk and Caeira met. It was the Hulk's rebellion against Red King's villainous nature, which let Caeira eventually become Hulk's wife. Then Caeira was destroyed by Galactus's arrival, losing her life.