The supporting character's harem is very normal - Chapter 12: Camouflage skill

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Being able to learn any skill immediately, and just by raising its proficiency, stand at the summit.

He is the World Chef Association Honorary Chairman, having the title of the World Chef God.

He is the greatest composer, pianist, and conductor after Beethoven and Mozart.

He also has the title of Underground Racing King, Fist King, Gambling King, Giant of the Stock Exchange Market, Arm of the Industries and King of the Skies.

He who has a miraculous learning ability and can stand at the apex of all things if he so wishes for it, the Omni Genius.

- Description from Novelupdates

In the vast and boundless continent Cangtu, there were ancient sects governing the Ten Old Domains, unworldly immortal clans beyond the Blue Sky, and primordial demon gods dominating the dark abyss that together created a great number of brilliant stories over the long course of the history.