Board Thread:Consensus Track/@comment-732150-20191023021841/@comment-1207741-20191023032549

They is generally taught as plural. Its usage as a singular is reserved for:
 * Individuals who have a gender/sex, but whose gender/sex is unknown to the speaker.
 * Individuals who have chosen not to be referred to with male or female pronouns.
 * Anecdotally, parents may also refer to their child as they until the child is old enough to choose their own pronoun.

The tailed beasts, meanwhile, are fictional monsters who physically resemble animals. Whether to refer to them as they seems like unnecessary sensitivity.