Mindfire
Istar
One way around the "now that the villain is dead, the hero is the most powerful one in the realm" trope is by having the hero's power lost in the final battle (the cost of destroying the villain), returning them to the status of a mere mortal.
I hate the trope. When the heroes train to the peak of power or collect all the magical plot artifacts only to be stripped of their power at or following the final confrontation. It just feels contrived. I mean, they did all that work and they don't even get to keep the power? THEN WHAT WAS THE POINT?