Rygar: The Legendary Adventure PS2 Q&A

Taking place on an Island in the Mediterranean Sea called Argus, Rygar: The Legendary Adventure, tells the tale of a noble warrior determined to save the Princess Harmonia and bring the Island of Argus back to a state of peace.
For his contribution and bravery during The Great Sea Battle, which ultimately brought the Island of Argus to victory, Princess Harmonia was honoring Rygar in a magnificent ceremony. During the celebration, ravenous monsters called "Titans" emerged from the land, destroying not only Rygar's homeland, but abducting his beloved Princess Harmonia.

In the midst of this chaos deep cracks were formed in the island's surface, creating a dark and mysterious underworld. Before realizing what was happening, Rygar was swallowed by this underworld.