Knights of the Zodiac (Saint Seiya), Vol. 17 — Masami Kurumada

At the Arctic Ocean Pillar, Hyôga faces Isaac, an old friend turned fearsome enemy. At the North Atlantic Pillar, Ikki is attacked by Sea Dragon, Poseidon's right-hand man, who seems strangely familiar. Could the evil Master of Sanctuary, whom the Knights defeated in their first epic battle, have returned to life? Seiya's beloved partner, Marin, confronts Poseidon and is overwhelmed by his godlike power. But Poseidon has yet to fully awaken, and another man controls him...a man the Knights may already know. What happened 13 years ago to set the Battle of the Gods in motion?