The best way to sex a Emperor Scorpion is by looking at the feathery looking pectines on the underside of your Scorpion. The males pectines are longer and more feathery looking than the females which are shorter. Males Emperor Scorpions are slightly smaller than females.
The easiest way to sex an Emperor scorpion is to look underneath it, at the genital operculum (genital opening), which is located next to the feather like structures. If this part of their body is oval shaped, it's a male. If it's heart shaped, or as I like to call it, looks like the head of a fly, it's a female.