Simple question really But Rhowen of Arkovia is mentioned from time to time and in three constatlation.
What I know is that he was a monarch who abdicated leaving the empire in the hands of the oligarchs and his stuff became constalations which would imply that either he was at least somewhat important.
Rhowen was the last king of Arkovia. Talk to the rovers (Imkala i believe) to give you more informatie and than there is the lore notes. https://grimdawn.gamepedia.com/Notes
In the long run though, his followers were spared from necromancer’s curse (despite technically being Arkovians), and his story deserved it’s own place on the night sky. Maybe if he had remained the king he could’ve prevented the Arkovia’s downfall, but who knows.