Ana emerges as a mysterious Servant operating without a Master, aligning with Merlin to assist Ritsuka Fujimaru and Mash Kyrielight during the Uruk Singularity crisis. She maintains an aloof distance from others, harboring undisclosed personal goals beneath her reserved demeanor. Her appearance presents a young girl with purple hair and eyes, typically concealed by a black hooded cloak marked with an eye symbol; beneath this, she wears grey armor and a metal headband bearing the same emblem. She actively defends Uruk against the Three Goddess Alliance and demonic beasts. Early missions see her accompany Ritsuka and Mash to investigate Ur, battling the Jaguar Warrior before the group retreats. Her combat prowess surfaces during Uruk skirmishes, including a confrontation observed by King Gilgamesh and the goddess Ishtar, who notes something unusual about Ana. Her weapon—a bladed chain scythe with boomerang-like capabilities—proves effective against supernatural foes, exemplified when she strikes Jaguar Warrior during a jungle mission. Critical aspects of her identity remain obscured initially. Enkidu identifies her weapon and eyes as capable of killing immortals, marking her a threat to goddesses, particularly the Demonic Beast Goddess Tiamat. This provokes Enkidu's attempt to eliminate her, forcing Merlin to teleport her to safety. Later revelations confirm she is an incarnation of the Gorgon Medusa, summoned as a child version. This explains her underworld connection, evidenced when Ritsuka enters that realm seeking the Tablet of Destinies in Kutha—a city linked to her lore. Her character evolves from detached observer to committed ally. She debates revealing her true identity to Ritsuka and Mash, but Merlin advises against it, positioning her as a strategic asset against Tiamat. Despite her origins as a being associated with death, she repeatedly protects Uruk's inhabitants and Chaldea's masters, demonstrating resolve incongruous with her nature. This internal conflict culminates during the climax against Tiamat. Shedding her child form, she reverts to her mature Medusa state to deliver the killing blow with her scythe, an act that requires her annihilation but ensures humanity's survival.