NEO HEROIC FANTASIA ARION

In a far-flung time when Gods and Men walk the earth together, the child Arion plays in the rolling hills of Thrace. His mother Demeter is troubled by both a curse - blindness - and by the secret of Arion's birth. A mysterious stranger spirits Arion away, and seeks to shape the growing young man into an assassin, a secret weapon to tilt the balance of the war between Zeus and Poseidon. But Arion won't be manipulated easily, nor will he submit quietly to the hands of adversaries like the tenacious Ares, the intelligent and fierce Athena, or the elegant and scheming Apollo. Only his tremendous strength, a forgotten weapon forged by Prometheus, and the love and loyalty of his allies can carry Arion forward. To discover the secret of his destiny, Arion will have to storm Mount Olympus- and face down Zeus himself!(Source: Discotek Media) — Description from AniList community (anilist.co).