Character who appears inUnder Night In-Birth. He is an assassin who currently works for an unknown client. A long time ago, Seth's ancestors were one of the many families that fought among each other in Night Blade. He also has some connection withLinne, as he wishes to save her from her curse of reincarnation. To achieve this, he seeks outThe Insulatorwho currently resides withHyde, which leads to them clashing in the events of the story. While Hyde doesn't want to end Linne's life just yet, Seth insists that he ends her life as soon as possible. JP:Kaji YuukiEN:Mark Whitten