Leatherwings
The library door was massive.
It was made of a dark wood that gleamed like metal and Belialthorn was sure it had the hardness of one. It was smooth except for the middle where words in a language he didn't know were engraved in looping silver.
He raised his hand to knock but the door swung open soundlessly, revealing an open space so large it reminded him of a market with both the size and busyness.
Then Belialthorn stared in shock because this was the largest population he had ever met in the castle. And they weren't humans, far from it.
Small and short, the size of a small cat but with a smooth muscular body lined with corded muscles that shifted under the thin brown clothes they wore. Their face was broad and ugly with fangs like needles and their eyes were black.
Leathery wings flapped softly behind them, easily holding them aloft.