The Healer Banished from the Guild Actually Had Infinite Mana, So He Becomes a Legend with Extraordinary Healing Magic

"No matter how far you go, you'll never be anything more than an errand boy!"
Fool, an F-rank adventurer who could use only Heal, a single-target recovery spell, was looked down upon as the guild's errand boy and lived an unfortunate life.
Fool was at a loss, but his encounter with Cecilia, a beastkin girl, would drastically change his fate—!?
Making full use of his infinite mana, Fool rises from the bottom to become a first-rate healer alongside his trusted companions!