As for Fevocius, he was an adventurer in a large city. In a very short amount of time, he was able to raise his rank and became a veteran in the adventuring business. That smooth selling road gave him extra confidence or rather over-confidence and he became an arrogant prick.
But his arrogance ended when a higher ranking adventurer beat him up and took his girlfriend before his eyes. For powerful beastkin there was a custom of betting their lovers or wives for a duel and Fevocius did just that. And then he lost measurably and was forced to lose both his pride and his girl.
After this humiliation, he was unable to live in the large city and also could not continue working as an adventurer. Wherever he went, he was made fun of. So he had no other choice but to run away. Now he did not want to be anywhere near a person stronger than him. So he decided to go to one of the less powerful nations where he could be the strongest with his powers.