Return of the Annunaki
These massive beings have humanoid forms twice the normal size of a human being, as well as potent inherent abilities, and their nature as native outsiders reveals their semi-divine natures, which much lore suggests that they were created by the gods, and abandoned on the Material Plane during a so-called ‘War of the Gods & Titans’. Their mysterious origin and separation from the rest of giant-kind, both culturally and physically, makes them easy targets for distrust and violence by humanoids and giants alike, and they are said to be unable to reproduce with other Large-sized humanoids, making them genetically incompatible with other native creatures like themselves. Nephilim PRD entry
Separately, the Valashai culture, known commonly as the Valashaians, are also giant-sized humanoids with incredibly distinctive, reptilian features, unrelated to other giantkin, and said to possess powerful psychic abilities, and connections to ‘the ancient gods,’ and while no Nephilim will admit it, they share a historical and genetic origin with this race, and their culture in prehistoric southern Tian Xia. The Valashmai Jungle expanse is named for their ancient culture, despite the small linguistic change in the name.