真の実力はギリギリまで隠していようと思う•Shin no Jitsuryoku wa Girigiri made Kakushiteiyou to Omou

I Think I'll Hide My True Ability to the Last Moment.

A world where you can contract with God and gain skills. Born as the third son of a famous knight family, Yuno was so busy controlling his innate power that he was eventually called "incompetent." However, in the magical knight academy, who was enrolled for some reason, he fulfilled his fateful encounter with an unnamed god who was despised as "incompetent" like himself. Yuno, who contracted with the goddess and named her "Athena," secretly decided to make her the highest god, and decided to get a little more serious. (Source: Kadokawa, translated)