Saikyou Degarashi Ouji no Anyaku Teii Arasoi

Arnold, the seventh Imperial Prince of the Adrasia Empire, is called "THE INSIPID PRINCE" among people since his twin brother is genius and respected by all people. However, he has a secret identity -SILVER, one of the only five -SS-rank adventurers in the continent. When his younger brother Leo decides to aim for the throne, Arnold starts running things behind the scenes to support his brother. Unexpectedly the most beautiful lady becomes his assistant. The secret struggle of the strongest prince begins!

(Source: Kadokawa)