My Disciple Has Become the Strongest Human Before I Knew It, and I, A Master With No Talent, Was Mistakenly Recognized as the Strongest in the Universe Beyond That

Uchi no Deshi ga Itsunomanika Jinrui Saikyou ni Natteite, Nanno Sainou mo Nai Shishou no Ore ga, Sore o Koeru Uchuu Saikyou ni Go Nintei Sareteiru Ken ni tsuite
うちの弟子がいつのまにか人類最強になっていて、なんの才能もない師匠の俺が、それを超える宇宙最強に誤認定されている件について

Adaptation

novel

After I was kicked out from my adventurer party, I lived out my retirement in the mountains. However, my disciple became the strongest human in the world without my knowledge, which started the rumor that her master could only be the ultimate strongest person, eclipsing humanity. Hence, I now occupied rank one on the adventurer rankings. An aspiring student, a dragon, a hero, and a demon lord all came flocking to me, completely misunderstanding everything. Please stop. I'm just a small fry, okay? This is not a story about an OP MC. It's a comedy about a bunch of idiots who think I am. (Source: Shousetsuka ni Narou, translated)