Russell Crowe's character is seen with glowing eyes and super human strength in the mummy. But no background information is given.
His evil-ish transformation seems to play no role in the movie plot, any clues?
Russell Crowe is playing Dr. Henry Jekyll, a well-known (to Anglophones, at least) character from an 1886 novel who invents a potion that regularly transforms him into an evil alter-ego, Mr. Edward Hyde. This character is one of the "monsters" that Universal Studios is featuring in its "Dark Universe" shared-universe movies, of which The Mummy is the first. I don't know why the filmmakers chose to feature him in this movie, but based on the reviews I've read, I doubt they knew either.