"Saint Seiya Omega" is a sequel to the original "Saint Seiya" series, set several years after the events of the previous story. The narrative centers on a new generation of Saints who protect the goddess Athena and battle against forces threatening the Earth. The protagonist, Kouga, is a young boy who becomes the Pegasus Saint after inheriting the Pegasus Cloth. Unlike the original series, where Saints relied on Cosmo energy, the Saints in "Omega" harness the power of the Elements, which are divided into Fire, Water, Wind, Earth, and Light.

The story begins with Kouga training under Saori Kido, the reincarnation of Athena, who has lost her divine powers. The peace is disrupted when Mars, a god of war, returns to Earth with the intent of conquering it. Mars seeks to create a new world order by using the Elemental Powers and enslaving humanity. Kouga, alongside other young Saints such as Soma, Ryuho, Yuna, and Haruto, embarks on a journey to stop Mars and protect Athena. Each of these characters represents a different Element, and their growth as Saints is a central theme throughout the series.

The first arc focuses on the battle against Mars and his army, the Martians. The Saints face numerous challenges, including internal conflicts and the revelation of Kouga's mysterious connection to Mars. After a climactic battle, Mars is defeated, but the victory is short-lived as a new threat emerges. The second arc introduces the god Abzu, who seeks to destroy humanity by unleashing the Pallasites, a group of warriors serving the goddess Pallas. The Saints must now confront the Pallasites in the Pallasite Kingdom, a parallel dimension, to prevent the destruction of Earth.

Throughout the series, the characters undergo significant development, both in terms of their abilities and their personal struggles. Kouga evolves from a reluctant hero to a determined leader, while Yuna, the Eagle Saint, grapples with her identity and purpose. Soma, the Lionet Saint, struggles with his loyalty and desire for power, and Ryuho, the Dragon Saint, seeks to honor his father's legacy. Haruto, the Wolf Saint, provides comic relief but also demonstrates growth as a warrior.

The narrative explores themes of friendship, sacrifice, and the burden of responsibility. The battles are intense and often hinge on the characters' ability to harness their Elemental Powers and unlock new forms of their Cloths. The series also revisits characters from the original "Saint Seiya," such as Seiya, Shiryu, and Hyoga, who play supporting roles and mentor the new generation of Saints.

"Saint Seiya Omega" concludes with a final confrontation against the true antagonist, Saturn, who seeks to reset the universe. The Saints must unite their powers and overcome seemingly insurmountable odds to protect Athena and ensure the survival of humanity. The series ends on a hopeful note, with the young Saints having proven themselves as worthy protectors of Earth and Athena.