A long while back I made a world system for a D&D campaign we referred to as IAS. There were several eras of evolution, and some of the older ones had larger and rather more aggressive forms that would later lead to IAS modern day species that are closer to standard enthros as we would know it. Most of these species petered out as more intelligent and adaptable ones replaced them, but the gods kept some of the old monsters and made them intelligent as servants and guardians long before anyone else arrived.

Compared to modern rats, the ancient rats were slender creatures about 7-9 feet tall with longer, more angular noses and a few fangs left. They had very subtle nose slits rather than full nose pads and their primary whiskers were set back more to their cheeks,

In the IAS setting, the most notable ancient rats were Talon, the first guardian, and Celeste, his mate who he resurrected as one of his own after leaving IAS to found a new home.