Nagini is the fictional snake owned by Lord Voldemort in the Harry Potter stories.
Nagini appears as Voldemort’s large, highly trusted snake and serves as both a companion and an instrument of his plans. In the novels, she is also revealed to be one of Voldemort’s Horcruxes, meaning that part of his soul is magically contained within her.
The name comes from naga, a term associated in South and Southeast Asian traditions with serpent beings. The Harry Potter character is fictional, however, and should not be confused with a zoological snake species. The films portray Nagini as a giant snake, but they do not establish a precise real-world species identification.
The character also appears in the Fantastic Beasts film series, where her backstory is expanded. This fictional portrayal has helped make the name familiar to audiences who may otherwise encounter naga-related serpent traditions in mythology and religion.