The Sun Rune is a True Rune that governs over the great power of the sun. It has traditionally been the property of the Queendom of Falena, and is normally sealed away in the Sun Palace in a bust. It had always been thought by the Falenan people that the Sun Rune was too powerful for any one person to be in control of it. According to legend, the Sun Rune was once synchronised with the Night Rune. However, once the Night Rune abandoned the Sun Rune, it would appear that the Dawn and Twilight Runes would instead be used to keep the Sun Rune's balance in power.
With the powers of the Dawn and Twilight Runes to balance it, the Sun Rune was said to be capable of nurturing life as well as destroying it. Legends also state that it was the Sun Rune’s out of control power that destroyed the Ancient Armes Dynasty and that a miraculous Sindar survivor would emerge from this devastation, bearing the rune and founding the Queendom of Falena.
When Queen Arshtat Falenas took the Sun Rune in order to prevent it from falling into the hands of her political enemies, she became more and more unstable and violent due to the rune's influence and power, becoming uncontrollably violent in moments where she was threatened or questioned. With nothing holding her back, she threatened to destroy Falena, but was slain by the swordsman Georg Prime before she could. The Sun Rune, without a host, returned to the bust in the Sealed Room in the Sun Palace.
Throughout the Sun Rune War, the Godwin Faction would attempt to gain access to the rune's powers and by the war's end, Marscal Godwin fled to the Ashtwal Mountains with it. Godwin sacrificed his life to the Rune so that it could take on a form to destroy his enemies. This attempt was foiled, and the rune returned to a peaceful state. With the war over, the Sun Rune was returned to the Sealed Room, and has remained there since.
- Genso Suikoden Kiwami Encyclopedia, pages 623-4