Who destroys Nagini in the Harry Potter books?

Neville Longbottom destroys Nagini in the Harry Potter books.

During the Battle of Hogwarts, Neville draws the Sword of Gryffindor and beheads Nagini. The act destroys the final known Horcrux protecting Lord Voldemort’s soul and leaves Voldemort fully mortal.

Neville acts after Voldemort has apparently defeated Harry in the Forbidden Forest. He resists Voldemort’s attempt to intimidate him, and his courage inspires other defenders of Hogwarts. The sword becomes available to Neville because he is a true Gryffindor and can wield it from the Sorting Hat.

A frequent mistake is to credit Harry with destroying Nagini. Harry destroys several Horcruxes, but Neville is the character who kills the snake.