Ergo is a traveling magician, and scoundrel who loves gooseberry pies. He has the ability to turn himself into various animals, including a tiger. Colwyn states to Ynyr that Ergo is one of the Hill Men and cannot use his magic for harm.
He is quite cowardly, but believes himself of immense quality and importance. He forms a strong friendship with Titch, even turning himself
Ergo and Titch
into a puppy so that Titch could have his only wish fulfilled, and saving him from a group of Slayers. He meets Colwyn, and Ynyr at the Forest outside of the Granite Mountains.