Centaurs

Centaurs in these stories are not riddles with hooves. They keep their own counsel, watch the sky, and resent wizard categories that call them beasts when a wizard wants the forest and ‘beings’ when a committee is feeling generous. The first book gives them a rescue and a warning. Later books give them a political grievance.

Canon fact: they live in the Forbidden Forest and do not consider themselves part of the castle’s staff. Reading their astronomy as a spoiler service for human plots is the mistake the humans make.