Krom is more of an assassin type while Edoarus goes for a butcheresque approach.
Krom prefers to hunt down single but powerful targets, he enjoys a good hunt.
Edoarus on the other hand does not care who or what he kills, he kills peasant and noble alike,
making no distinction whatsoever.
Edoarus is more of a silent, brutal and kind of humorless character (he would have had some
missions with Meya btw). Krom is more of an ironic and sarcastic character.
Above everthing else, they are both killers, however. In a 1v1, Krom would most likely win though
there is no reason for them to fight as they are both loyal subjects of Aridon - and Rahandir
is the only Undead who has complete free will due to being reanimated by himself rather
than Aridon.
Yes, Ornasion is also more free than other Undead due to his powerful status both in life and
death and Aridon is allowing his underlings some freedom, but Rahandir is the only Undead who
still knows actual freedom - yet he decided to serve Aridon no questions asked.