She is the main villain of the game and is the leader of Todo's ninja and later becomes the leader of a group known as the Burning Dawn, she believes in creating a world for ninja with the assistance of the Burning Dawn and fellow ninja who believe in her vision. She first appears during the attack on Gohda castle where her ninja assist the rebellion and later appears at Todo's camp watching Ayame from afar before beheading Todo after he is mortally wounded by Tatsumaru, she takes the head to a cliff and burns it as a signal for her ninja to kill Todo's men and the birth of the Burning Dawn. Tatsumaru follows Kagami and the pair fight each other as the other Azuma ninja arrive on the scene and can only watch on in horror when they both fall into the sea presumably drowning. However it is revealed that she survived along with Tatsumaru who is suffering from memory loss, Lady Kagami drags him ashore to the Kansen Caverns and uses this opportunity to recruit Tatsumaru as the final Lord of the Burning Dawn replacing Seiryu the blue dragon who he killed during the attack on Gohda castle. Kagami reveals a massive warship the Fire Demon which she plans to use to challenge those who oppose her, the ship contains enough armor and weaponry to challenge the best samurai and plans to use it to craft her dream into a reality.
The construction of the Fire Demon had fell behind so Kagami sends her Lords to kidnap villagers from Gohda's province while Burning Dawn operatives such as Kamadoma on Demon Mountain ran similar operations. Kagami also hired the help of the chinese Baliosung Gang to kidnap more villages and hold them in a small fort on an island. Eventually these actions were discovered resulting in Rikimaru killing Kamadoma on Demon Moutain saving the captives and discovering Kagami's secret harbour where she was transporting slaves. Meanwhile Ayame followed the Burning Dawn to Kubon Island and killed Wang and the rest of his Baliosung gang freeing the prisoners there. Angered Kagami planned an attack on the ninja village and sent Suzaku the Red Sparrow to distract Rikimaru by attacking a temple and she sent Tatsumaru to attack the secret quarantine village where Ayame was later sent to defend, with both Azuma ninja absent Lady Kagami and Tatsumaru attacked the ninja village with several ninjas from the Burning Dawn. Kagami witnessed Tatsumaru wound Lord Gohda and kill his former master Shiunsai before Rikimaru returned and engaged Tatsumaru, after beating him in battle he failed to take his advice and kill him giving Lady Kagami the opportunity to disarm him allowing the pair to flee past Ayame to the Kansen Caverns.
A Romance had begun to develop between Tatsumaru and Lady Kagami as her vision begins to take form, meanwhile Ayame had followed Kagami and confronts her after the attack on the ninja village provoking her to fight but she is calmed by Tatsumaru who reminds her of the dream causing her to feel ashamed for her outburst and leaves to begin preparation for her plans leaving Tatsumaru to finish off Ayame. Later the Azuma ninja find Lady Kagami and Tatsumaru in the Burning Dawns hideout and discover her plans to use a newly constructed battleship to lead a fleet against Gohda castle and begin a new era for all ninja, Ayame sneaks on board while Rikimaru returns to Gohda castle to inform Lord Gohda of the events and what had been discovered. After realising she had been discovered by the Azuma ninja Lady Kagami launches the complete Fire Demon before a defence force can mount against her and heads for Gohda's province where the attack commences on Gohda castle with the Azuma ninja determined to stop Lady Kagami and the remaining members of the Burning Dawn.
Rikimaru confronts Lady Kagami on the deck of her ship where she expresses her hopes and dreams for all ninjas and how she wont let anyone stop her vision from coming true. A fierce battle ensues ending with Rikimaru mortally wounding Lady Kagami before leaving her to die, as Lord Gohda prepares to destroy the ship with a flaming arrow attack Lady Kagami stumbles upon the body of Tatsumaru. She cradles him in her arms and dies just as the barrage of arrows ignite a cache of explosives destroying the ship and putting a stop to her plans.