Having a hearing enhanced enough to form a mental image of their surroundings is probably also useful at picking up information others don’t notice (like we’re able to tell the difference between hot and cold water pouring from the sound alone, but cranked up to 11). Also they wouldn’t need to scream, tongue clicking is enough
Tag: echolocation
for the echolocation knack, look up “Human echolocation – Daniel Kish, ‘Batman'” the borrower wouldn’t have to scream
The part in the ask was just a joke, and for most borrowers, echolocation wouldn’t be a useful ability, as they can all see in the dark from their time living in the walls. The Grace allowed them to adapt to the life they live quickly.
This would be a very useful ability for a blind borrower, along with a few others that also enhance senses.
Brothers Apart 