"I saw a Aegis once. Cute little bastard got my leg." - Issac, a drunken dwarf.Edit
The structure is similar to that of a cat except it's body appears to be filled entirely with dark matter. The dark matter is incredibly powerful and potent which can be crafted into anything.
They have an above average inteligence and are far smarter than humans. They have command over a mysterious magical force that isn't seen or usable by any other being. They use this mysterious force to trick their attackers into not going after them.