The Moon Rune is a True Rune representing destruction and compassion. This rune also turns its bearer into a vampire. This rune carries with it a huge curse, as it actually dominates its bearer's mind until s/he gains mastery over its powers. It also makes its bearer immune to a normal sword or magic. It is a huge mystery if the rune only recognizes its first bearer Sierra Mikain as its master because, Sierra is immune to aging, bloodlust, religious figures and artifacts, and sunlight. Moreover, despite being separated from the rune for a very long time and Neclord is its current bearer Sierra still has complete control of the Rune.
When Sierra came into possession of this rune, she ended up going on a killing rampage, forcing her to retreat into the forest to keep herself from harming others. As she gained mastery over this rune, she was able to tap into the powers of compassion, which diminished her vampiric impulses to drink the blood of the living. This led to the creation of the Blue Moon Village, where Sierra lived with others who had cast their pasts away, such as Rean Penenberg and Neclord. Since then, Sierra removed the Moon Rune from herself and placed it on an altar at the center of the village. However, Neclord, overtaken by the lust for power, stole the Moon Rune and fled, robbing immortality from the villagers other than Sierra. Some of the villagers fled to sustain their immortality through sucking the blood of others.
Although the rune made no appearances nor was mentioned in the Toran Liberation War, Neclord has the rune with him and used its powers to create a doppelganger of his.
The rune was first used by Neclord to destroy Riou. He sacrificed enough blood and lives in order to be able to use its curse however, because Riou had the Bright Shield Rune with him it was able to negate the curse. Neclord tried to use its powers again when he cannot escape the barrier casted by Kahn Marley but Sierra commanded the Rune to deactivate. Sierra asked Neclord to return the Rune he stole from her. Fearing for his life, Neclord immediately passes the Rune to Sierra. The Rune is then reunited with its first and original bearer and has been with her ever since.
Blue Moon CurseEdit
The Blue Moon Curse is the power of the Moon Rune. During the Dunan Unification War tried to use the curse against Riou. Nanami told Riou to run away but Neclord stated that those that are still alive cannot escape from the curse. However the curse was rejected because of the Bright Shield Rune that protected Riou. The magic requires the blood of 100 people. Neclord sacrificed the blood of 100 people and the lives of 100 people as a sacrificial offering. It is also revealed that if the sacrificial offering was enough, it can blow away a sacred barrier.
- The rune has never forgotten Sierra Mikain as it's true bearer no matter how many years Neclord had in possession of it.
- Despite getting the True Rune upon defeating Neclord, it cannot be used in battle. In fact, it does not appear in any of Sierra's rune slots.
- The rune's name is object to misconception. Many fans think that the rune's name is Blue Moon Rune, although the rune itself named as "Moon Rune" both in Suikoden II and Suikogaiden Vol. 1. The misconception probably took its root from Blue Moon Curse and Blue Moon Village, both got its name from "Moon Rune".
- The Moon Rune has power over the destruction and compassion, aspects shown by Neclord and Sierra, respectively.
- When Neclord uses the power of Moon Rune against Riou, it's similar to the power used by Yuber to invoke the Bone Dragon in Greenhill.