Sev is a yuan-ti pureblood prisoner held captive in the Fane of the Night Serpent. He appears human except for his forked tongue—a characteristic feature of yuan-ti purebloods.
Condition
Sev is suffering from blue mist fever, one of the diseases found in Chult (detailed in the Diseases section of the adventure). The fever causes him to experience vivid hallucinations: he throws stones at illusory blue monkeys that only he can see. This delusional behavior makes him particularly vulnerable and unpredictable.
Circumstances
Like the other prisoners in the temple, Sev wears manacles on his wrists and ankles and has been stripped of armor and weapons. The yuan-ti are holding him until he can be sacrificed to Dendar the Night Serpent. Despite being a yuan-ti pureblood himself, he receives no special treatment from his captors and faces the same grim fate as the other prisoners.
He is one of ten prisoners described in area 7 (Oracle Pool) of the Fane of the Night Serpent, all of whom seek to escape the temple and return to civilization.