The Poseidon saga was the second of the three instalments, though in the anime series the Asgard arc was attached to it. Poseidon, by the machinations of Gemini Saga's evil twin Kanon, has awaken to soon, and raises his armies.
These forces are led by Marina Generals, or Marinas for short, warriors with a power level equal to a Gold Saint. With the forces of Sanctuary seriously depleted, he hopes the few remaining Gold Saints would take up the battle, but instead the Bronze saints arrive in his realm, even though some Gold Saints like Aiolia would have gladly joined. However, the signs are near that Hades is about to awaken, so Sanctuary cannot risk losing more of it's elite warriors...
The world is gladly running under as sea levels rise due to non-stop rains, and Athena agrees to keep the levels acceptable by storing herself in the Central Pillar of the mythical home of Poseidon, Atlantis. The Saints must try to topple this pillar, but inorder to do this, they first need to destroy seven supporting pillars, each guarded by a Marina.
The first Seiya and his friends encounter is the Sea Horse general, Baian, Guardian of the Northern Pacific pillar. He is a fierce loyal warrior to Poseidon, and willing to give up his life for his deity. He attacks using strong windbased attacks, including tossing Seiya through the roof of the underwater realm and send him back crashing to the floor.
He then realised that Baian's techniques where about the same style as the Silver Saint Misty used, creating air currents with his hands. When he awakened the Seventh Sense, Seiya's bronze armour, revived by the blood of the Gold Saints, started shining gold and greatly, yet for a limited time, raised his powers and bringing him to an equal level of Baian. This allowed him, using the expeerience from fighting Misty, to overcome the Sea Horse general and with the help of the Libra cloth destroy the pillar, leaving Baian mortally wounded.
Sea Horse Baian has been released as a Myth Cloth, but is unfortunatly not yet in my collection.