What direct characterization details does the author provide when Rainsford sees the man who opens the door

We learn that Ivan is big and scary looking:

The first thing Rainsford's eyes discerned was the largest man Rainsford had ever seen--a gigantic creature, solidly made and black bearded to the waist. In his hand the man held a long-barreled revolver, and he was pointing it straight at Rainsford's heart.