The statue is actually an empty shell, the remains of one of the two Sept-Terrions that engaged in the fight that led to the creation of the Great One around the time of the Great Collapse. This particular vessel was Ark Rouge who was balsted her after the clash near the Osgiliath Basin.
Although the island is currently uninhabited, there are still ruins of an old settlement. The ancient Bryonians lived in stone-made cottages reminiscent of igloos. They lived here until the Middle Ages, after which they abandoned the island.
The Bryonians were traditionally animists, who offered prayers at an altar. In S.1206, when Rean Schwarzer and Class VII light the animist statues spread throughout the island, the altar reveals itself as the Sol Shrine (陽霊窟).
Class VII's Group B travel to Bryonia Island during one of of their field studies. This event is not seen in game, but is mentioned. The participating members comment upon the giant stone figure.
Rean and the new Class VII come to Bryonia island during their field exercise in the Lamarre region. Rean is on the hunt for Millium Orion whose trail ends up here. After exploring the island, they discover several animist monuments that, when combined with Emma's Hexen pendant, together reveal the Sol Shrine. Inside, Rean faces the Stahlritter and Arianrhod who are using the location's mana to charge the Aion Type-α II.
Rean and his companions return to the Sol Shrine to meet up with Crow Armbrust and Duvalie who is assisting him. There, Crow reveals to them the purpose of the Rivalries and starts the first one, in which Valimar and Ordine fight to the death. Valimar wins and starts to absorb the other knight, which will end Crow's life in the process. Rean stops this and Ordine becomes a vassal of Valimar, saving Crow, at leats until the rivalries are done. They stay at the lodge in the aftermath, with them inviting Duvalie to join them.
One of four legendary fish is found behind the waterfall.