What he actually is made of is unknown, but has a more solid liquid state and shadow like state, and are almost undistinguishable.

At first Shadow is a bit skittish but when trust is gained he acts like a excitable puppy, this goober is also known to be mischievous like mimicking others in how they look but a bit more intimidating >:3
He is unable to speak so the only ways he can communicate is nodding his head and sign language
Shadow also loves pets, hugs and loves giving hugs too ^w^

( I guess in this drawing he technically loafing so that's why his other 3 hands are being hidden )