Lady Vasarus's cave is a cave in the Peacebond which previously housed Lady Vasarus. It was therefore also Little One's childhood home.
Lady Vasarus had a water entrance she could fly in and out of. Supposedly the cave entrance was also enchanted in a way that deluvians couldn't find the entrance. There was also a way to a private little beach, Little One and his mother would sometimes go there to train.
There was also a small part of the cave, where Lady Vasarus hid a bit of treasure for her son away.