Here's why:
* Reflexive pronouns refer back to the subject of the sentence. They are used when the subject is both the performer and the receiver of the action.
* Examples:
* "She hurt herself."
* "The children enjoyed themselves at the park."
However, it's important to note that "themself" is considered non-standard English. The correct reflexive pronoun for the third person plural is "themselves".
While some people might use "themself" as a gender-neutral alternative to "himself" or "herself," it's not widely accepted as grammatically correct.