The Night Rune (夜の紋章, Yoru no Monsyou) is one of the 27 True Runes. It is currently in the form of the Star Dragon Sword.
Suikoden
Just prior to Viktor delivering the final blow to Neclord, the Star Dragon Sword stated that he was the Night Rune itself, but transformed[1]. As such, Neclord was a servant of the darkness that the Night Rune represents and so fought him in vain[2].