Since protecting the empire was Erick's duty, he could not expend his mana as he pleases. When he uses magic that uses up a lot of mana, he had to always reserve a certain amount in cases of emergency.
He can't use up his mana until he almost runs empty. He had to ensure he could teleport multiple times using his mana alone in case he lost his scrolls or magic tools. He had to be ready to take the Emperor to safety any time the need may arise.
Healing a lot of knights and soldiers uses a great deal of mana. Thus, he could not heal them back to their normal health just as he did to Hendrick. He healed all the injured though until their wounds closed off. They still have to lie low and recuperate though since healing so many people limited what he could do.
With his duty done, he was set to leave. And yet, Duke Henry and Marquess Hendrick had made him run an errand.
