Tsuki Aya

Born Tsuki Aya, she had a loving mother and father, and an older sister named Mai, who looked after her. She is the only immortal archangel, being the embodiment of Death itself, and is also very beautiful. She was the youngest Archangel on the Celestial Council, due to her intellect and compassion for her people. Her beauty, however, was troublesome for her, as she began receiving proposals from strangers. She denied these requests due to how young she was, and lack of knowing who the suitors were. Azmodeus was driven to madness by this beauty, and killed her parents and sister to prove his worth. Traumatized, she hid herself away, mourning the loss of her family. 2 days later(506 earth days, or about 1.5 years), Azmodeus declared war on Heaven, so as to take Aya's hand by force. She was the sole survivor of the Celestial race, due to her indestructibility. She used the remains of her people to create a new, unique race called Reapers. By chance, she reincarnated her elder sister, and named her Mai.

Throughout most of the first project, Aya plays the role of the primary antagonist and main character, before the roles switch in the seventh game, where it is shown that she is not the enemy, but the victim of the protagonist's employer. This causes a twist in the plot, as it is revealed that Yamakawa is Azmodeus in human form. He had been trying to capture the archangel not because she was a threat, but because he wanted to enslave her. This causes the player to turn on Yamakawa, and fight him.

While not very strong, she is both intelligent and quick, utilizing her speed and surroundings to dodge attacks and strike her opponent with deadly accuracy. She wields a legendary sword named Kage no Dansu, which she artfully uses to defend herself by bouncing bullets back at the player. She is short-tempered with those who joke about her height, and will cut them down a foot or two so she can yell at the offender face to face.

Her name means 'Colorful Moon' in Japanese.