A-20 is a young female Twin Blade in The World whose carelessness and motivations for playing help Mimiru to realize her own reasons for playing the game. A-20's reasons for joining the game are revealed to be its popularity among her classmates and her desire to complete a difficult dungeon to prove her valor. In real life, "A-20" is her student number at school, along with A-1 through 19; her classmates who are only mentioned. After getting a rare Golden Grunty item (which she describes as "ugly"), she decides to collect them. After this, she continues adventure with Mimiru in The World on occasion.