Asia Argento is an attractive young girl characterized by her long blonde hair and striking green eyes. She has body measurements of approximately [B83→85-W55-H81→83 cm], stands at [155 cm] (5 feet 1 inch), and weighs around [44→45 kg] (97→98 lbs). Her hair cascades down her back, featuring split bangs that frame her forehead and a single strand that sweeps backward from the top.

Originally, Asia wore a distinctive dark teal nun outfit highlighted with light blue accents. This was complemented by a white veil adorned with light blue detailing, a brown satchel resting on her right hip for her Bible, and brown boots secured with black straps arranged in an X pattern. She also wore a silver cross necklace, which she was later compelled to remove after becoming a Devil.

After transferring to Kuoh Academy, Asia adopted the school’s female uniform, which includes a black sweater vest worn over her dress shirt, replacing the cape and corset that were part of her previous attire.

Asia Argento is characterized by her extreme shyness, innocence, and relative inexperience in social situations. As a former nun, she is a devout Christian who continues to believe in God even after her reincarnation as a Devil. Asia adheres to her faith by praying and reading the Bible, though these actions often lead to severe headaches. Her inherent kindness is remarkable; even during her human life, she harbored no animosity toward Devils and treated everyone equally, regardless of their nature. Azazel noted that her unconditionally compassionate spirit compels her Sacred Gear to heal even her enemies, as she cannot ignore the suffering of others. The revelation from Kokabiel that the God of the Bible was killed during the Great War left her in deep shock.

Although she initially struggled to adapt to her new life as a Devil, Asia has come to realize that her friendships, comrades, and her connection with Issei Hyoudou and his family hold greater importance than her faith alone.

Asia’s purity draws others to her, making her well-liked. Her charm is so profound that she was able to tame Rassei, a Sprite Dragon, which is typically unmanageable by Devils; such creatures are usually only tamed by those with pure hearts. Azazel remarked on her exceptional talent for taming Dragons. After receiving Ophis’ blessing, she successfully formed a contract with Fafnir, one of the Five Great Dragon Kings. Following her successful taming of four mass-produced Evil Dragons, she gained recognition in the Dragon world, becoming known as the Dragon Priestess (龍の巫女, Ryū no Miko), a title usually reserved for Evil Gods.

Due to the peculiar requirement of giving away her panties each time she summons Fafnir, Asia often feels embarrassed, especially when she sees Fafnir consume them, leading her to escape into her own thoughts, lamenting her association with such items. However, after witnessing Fafnir’s determination to protect her against Rizevim, she has learned to set aside her embarrassment during battles, focusing on the fight rather than her modesty.

Asia enjoys agricultural work, often engaging in gardening and planting. She has expressed a desire to live with Issei in the countryside of the Underworld, where she envisions herself cultivating crops and engaging in various forms of agricultural labor.

As her relationship with Issei develops, Asia becomes more assertive, particularly when she notices other girls growing closer to him. Initially viewed by Issei as more of a sister due to his protective nature, she felt sad and developed a slight inferiority complex when comparing her appearance to that of Rias. This jealousy manifests in her pinching Issei’s cheeks whenever he shows interest in other girls. Asia wishes to be treated as a woman by Issei and desires his attention, even expressing a wish to bear his children. After a significant moment at the Sports Festival when she kisses him, Issei begins to see her more as a romantic partner than a little sister. Asia holds Issei in high regard, expressing a desire to stay with him forever and even indicating a willingness to become his servant. Despite her shyness, she fiercely protects Issei, even striking Diodora for insulting him.

After becoming Issei’s servant, Asia demonstrates increased courage and determination in battle. In a Rating Game against Team Rias Gremory, she bravely stayed behind to confront Crom Cruach alone, allowing Xenovia and Irina to advance and conserve Issei’s stamina. Crom Cruach admired her bravery and tenacity during their confrontation. Asia showcased her ability to use offensive Magic, contrasting her previously passive nature. She continued to fight Crom Cruach even after Fafnir was defeated, declaring that as Issei’s servant and future wife, she would keep fighting until the end. This declaration deeply impressed Crom Cruach, who praised her spirit and courage, stating it was an honor to battle her and Fafnir.

Asia’s backstory as depicted in the anime.

Asia Argento was abandoned by her parents as an infant, left in front of a church where she was raised. During her childhood, she awakened her Sacred Gear, Twilight Healing, when she healed an injured puppy she had found. This act was witnessed by a member of the Catholic Church, leading to her being regarded as the Holy Maiden. Despite this recognition, Asia struggled with loneliness, as many viewed her as a monster capable of healing wounds rather than seeing her for who she truly was.

At one point, Diodora Astaroth orchestrated a scheme to manipulate Asia into healing him, a Devil. This deception resulted in her being cast out from the Church, with the public labeling her a “witch.” Left with nowhere to turn, Asia found herself relying on the Fallen Angels for support.

• Twilight Healing (聖母の微笑トワイライト・ヒーリング, Towairaito Hīringu): Asia’s primary Sacred Gear and weapon of choice, Twilight Healing enables her to heal Humans, Devils, Angels, and Fallen Angels. Lacking actual combat skills, she serves as the healer for her team, relying on her restorative abilities. Asia has learned to expand the range of her healing field and can project her healing powers as projectiles, though these are less effective than direct contact. In Volume 11, Azazel noted that Asia has mastered her Twilight Healing more than other users of similar powers. Additionally, she can create a bow and arrow made of healing energy; however, if the arrow is aimed at an enemy, it will disperse instead of causing harm.

• Twilight Saint Affection (聖龍姫が抱く慈愛の園トワイライト・セイント・アフェクション, Towairaito Seinto Afekushon): This sub-species Balance Breaker takes the form of Golden Dragon Armor adorned with red jewels. It grants Asia a field of absolute defense and protection for a limited duration. While active, she can envelop an area in powerful healing energy, negating any damage from virtually any source—not by nullifying the attack itself but by preventing the damage it would inflict. Additionally, as Fafnir’s aura is included in this ability, it enhances her defensive capabilities alongside her healing powers. Asia can use this form to heal multiple allies simultaneously across a wide range, demonstrated when she healed allied youkai during the Evil Dragon War.

• Bishop Piece (僧侶の駒, Sōryo no Koma): Asia was reincarnated using a Bishop Piece, which enhances her magic power and abilities.

• Dragons: Asia has formed pacts with various Dragons, thanks to Ophis’ blessing and the assistance of Azazel, Rias, Rossweisse, and Akeno. She can establish connections with different classes of Dragons, including higher-tier ones like Fafnir, the Golden Dragon King. Asia utilizes Fafnir and the four Evil Dragons she has tamed to protect herself, allowing her to focus on healing her comrades.