Let This Grieving Soul Retire, Vol. 1 (manga)

"There’s only one thing I’m aiming for-to be the world's strongest hero." 
Cri makes an oath with his friends to become the strongest hero in the world...but his hopes are quickly dashed when he realizes that his talents lie elsewhere. Despite the reality check, the expectations from the people around him seem to rising exponentially every day! Now Cri must deal with this huge misunderstanding as well as the outrageous consequences!