In short you if you join Citra, Jason will copulate with her in a fertility ritual. After Jason finishes, Citra will sacrifice him with the ceremonial dagger. As Jason dies, Citra explains that the ...

is the leader of the local tribe on the island, the Rakyat. "Known to the rebels as their warrior goddess, Citra is cloaked in the mystery of old ritual and superstition. Charismatic and beautiful, ...