Saikyou no Madoshi. Hisa ni Ya wo Ukete Shimatta no de Inaka no Eihei ni Naru

Also known as: 最強の魔導士。ひざに矢をうけてしまったので田舎の衛兵になる, I Used to Be the Strongest Sorcerer. Then I Took an Arrow in the Knee and Became a Village Guard, The Strongest Wizard Becomes a Countryside Guardsman After Taking an Arrow to the Knee, 最強的魔導士，膝蓋中了一箭之後成為鄉下的衛兵

by Gingitsune Ezo

The strongest wizard Alfred, in a hero’s party, subdued the Maou and in the process took a cursed arrow to the knee. Even with the hurt knee, Alfred’s still the strongest wizard ever. "We need a chief for our newly created knight squad!" "Could you help us as our guild manager?" "We need someone to rid us of the dragon that resides in the North Mountain." Alfred just wanted some time to rest and recover, but no one would LEAVE HIM ALONE. Because of that, Alfred wished to spend time recovering in a small country village that no one knew about. "Need a guard in Mulg Village. Wolves and boars attacking the village. Payment is food and board. *Village has a hot spring." So, the strongest wizard in the kingdom decided on living the slow life in the country