SeaHorse Baian is the first Marina General that the Saints of Athena battled, in Masami Kurumada's manga, and therefore in its anime adaptation.
Baian was a powerful warrior, loyal to Poseidon in the same way as Athena's Saints pledged their loyalties to her. Faithful to his god, Baian was willing to risk his life to protect the Mammoth Pillar that was entrusted to him. His power was said to be the same or superior to that of the fabled Gold Saints of Athena. Pegasus Seiya himself stated so after his encounter with the feared Marina General.
Seahorse's fighting style was powerful and deadly. He attacked Seiya using his mighty God Breath, which was a gale of immense destructive force, and his Rising Billows, his strongest attack, that as its name says, was a powerful rising tidal wave capable of sending the enemy from the depths of the seas to its surface. Baian's offense was complemented by effective defensive tactics.
When the Bronze Saints had reached the Poseidon governed Submarine Sanctuary, they learned that the only way to save Athena was to destroy all the Mammoth Pillars holding up the seven seas. Pegasus Seiya was the first to encounter one of the Sea Generals, who was guarding the North Pacific Ocean pillar.
Seiya tries to destroy the pillar with his Pegasus Ryu Sei Ken, but Baian appears and extinguishes his bolt merely with his hand. Pegasus attacks again, but his hits are blocked by some sort of barrier. Baian then uses his technique, the God Breath, and throws Pegasus against the pillar. Then, the General uses his Rising Billows; this immensely powerful attack launched Seiya against the submarine roof. After surfacing, Pegasus comes back to his enemy. Something unexpected happens, as the Pegasus Cloth begins to shine with a beautiful golden radiance. Baian is amazed and wonders why the Bronze Pegasus Cloth shines as if it was a Gold Cloth. Seiya, although himself amazed as well, finds the answer. His Bronze Cloth was revived by the burning blood of the mighty Gold Saints, after the Twelve Temples conflict, being imbued with immense power and endurance. Because of this, when Seiya's Cosmo reached his seventh sense, the Bronze Pegasus Cloth awoke its new power, and became almost as impervious and powerful as a Gold Cloth
Realizing that they might very well be fighting in the same terms, Baian engaged the Pegasus Saint once again. This time Seiya's attacks break the General's barrier and hit him. Baian says that his Scales is invulnerable, but after a split second the armor fractures. Pegasus launches another Ryu Sei Ken and obliterates his enemy, destroying the SeaHorse Scales, whose hardness and endurance was said to be equal to that of a Gold Cloth.
After a bloody exchange of blows, Seiya realized the power of the Seahorse Marina was one to be respected. But during the clash, he managed to discover the secret to Baian's effective invisible shield. It was nothing more than an air current created by his hands, the same technique the Silver Saint Lizard Misty, whom Seiya defeated long before, relied on.
Due to the fact that the pressure of the sea water was higher in Poseidon's Temple, Baian was somewhat slower than Misty in creating his Air Barrier, and this allowed Seiya to discover Baian's secret.
Remembering his battle with Misty, and benefitting from the experience he gained in it, Seiya was able to overcome Baian's Air Barrier in the same way he did with Misty's and disabled it with his Pegasus RyuuSeiKen. Never willing to abandon Athena, and leaving Baian defensively crippled, Seiya renewed his unrelenting attack on the mighty Marina, until he achieved a complete victory.
The SeaHorse Scales represents the mythological being that Poseidon, Emperor of the Seas, used to pull his chariot. It is depicted as a fish-like horse with several fins.
As the SeaHorse Scales depicts a mythical scale-covered being, it bears a resemblance to Pisces Aphrodite's Pisces Gold Cloth.