The Brilliant Healer's New Life in the Shadows: Volume 1 (manga)

Zenos hails from the slums, but he won't let that stop him from paving his own path to success when he chances upon a healer and begins learning the curative arts. When an adventuring party extends him an invitation, Zenos is elated—only to find himself treated like dirt. Despite honing his skills to perfection, the party deems him useless and kicks him out.Now broke and out of luck, Zenos starts an illegal clinic, becoming a shadow healer. Word of his genius quickly spreads through the city's underbelly, but as his reputation grows among the dregs of society, word of Zenos's ability reaches the wrong pair of ears…