Aya is the older half-sister of Uesugi Kenshin. She initially appears as a unique NPC in the original Samurai Warriors 3, before being made as full playable character in the Xtreme Legends expansion. She is a calm and composed woman who cares for the priority of her clan more than any other of her gains. Aya is respected by both Kenshin, who holds her as a "goddess", and her clan's retainer, Kanetsugu Naoe, who looks up to her as a teacher. In the game, she mainly supports her brother's campaigns while also taking Kanetsugu as an apprentice. However, after Kenshin's death, she opposes one of his possible successor, Kagekatsu, and Kanetsugu, supporting his other successor, Kagetora, instead. After defeating Kanetsugu, he is ashamed that he has swayed too far from Kenshin's ways and attempts to take his life, although Aya stops him, telling him that she is willing to see how he handles the Uesugi's future. Her weapon is a magic staff.