Gudako (ぐだ子?), also called the Nameless Master or Master without a Name and Ritsuka Fujimaru, is one of the main characters of the Learn with Manga! FGO series. She is the Master of Berserker.

Gudako exhibits a noticeably erratic and eccentric personality characterized by an all-consuming addiction to gambling on gacha. Belligerent, impulsive, and volatile, she often berates, harasses, and abuses the people around her in various ways, particularly her Servants. Gudako seemingly has a love/hate relationship with rolling gacha: while she often demands Saint Quartz in order to facilitate rolls and goes into manic fits of excitement upon learning that she can play the gacha, she also warns other people to stay away from gambling on gacha and cites it as being a hell she can’t escape from. Even so, her attitude towards her Servants is incredibly poor. She discards low-rarity Servants as worthless, and treats her high-rarity ones little better, frequently neglecting or assaulting them.