Hanging back (but at the same time, he does not act submissive - if anything, his position as they walk is that of 'defense', keeping guard behind them) as they approach, Skellig is struck a bit at just how...big...Koshchei is.

Clearly, he has been laboring and fighting for quite some time!

However, he does not puff himself up or try to appear bigger himself - while he might be built much leaner than this man, he is still solid, and still quite able to defend himself (and his mate) if needed.