Balin and the Hollow Knight (en Inglés) - Larry Pearson

When the world's oldest magician appears to lose control of his magic, a boy and a frog step forward with a most unusual plan to save him.

The hollow knight that - almost - comes to life through their efforts joins them in a quest to solve a dragon problem created by the wizard's magic gone awry.

Magic and technology sometimes help, sometimes create new obstacles as their paths cross this of fantastical beings who do not necessarily have their best interests in mind.

A witch, gnomes, an ogress, and a troll all complicate their lives.

About the frog. He says he was a prince. Yes, he talks. Will he become a prince again, or is he doomed to a life of eating flies?