Three details used by Richard Connell in the characterization of ivan?

Big ominous looking guy,

"a gigantic creature, solidly made and black bearded to the waist."

Dressed in some sort of military uniform,

"He was dressed in uniform--a black uniform trimmed with gray astrakhan."

Ivan is strong, deaf and dumb.

"Ivan is an incredibly strong fellow," remarked the general, "but he has the misfortune to be deaf and dumb. A simple fellow, but, I'm afraid, like all his race, a bit of a savage."