Ain

Biodata

Feature	Information
Name	Ain (艾恩)
Gender	Female
Affiliation	Seventeenth Division of the Whitebeard Pirates
Occupation/Role	Zephyr's student; Lin Yan's secretary and companion
First Appearance	Chapter 35

Power Progression

Stage / Realm / Level	Chapter	Notes
Backward-Backward Fruit user and swordswoman	35	Revealed as Zephyr's student and a Devil Fruit user whose touch regresses a target by twelve years.
Swordmaster-level swordswoman	209	Her pre-existing swordsmanship is identified as having reached the Swordmaster Realm.
Dragon-enhanced combatant	209	The Holy Grail of the Underworld reconstructs her body, granting exceptional physical ability, dragon-scale-like defense, elemental control, and dragon transformation.
Admiral-level combatant	211, 252	Her transformed strength is assessed as capable of rivaling an Admiral; she later overwhelms Beasts Pirates forces and battles alongside Boa Hancock.

Background

Ain lived as the student and loyal follower of former Marine Admiral Zephyr. When Lin Yan arrived at Zephyr's secluded Sabaody residence, she intercepted him and attacked with the Backward-Backward Fruit. Lin Yan trapped her in Mangekyō Sharingan genjutsu, causing her Fruit ability to strike a tree rather than him, and defeated her within ten minutes. Despite her resistance, she led him to Zephyr after he demanded a meeting. 35

After Lin Yan killed Edward Weevil and offered Zephyr a place in the Seventeenth Division, Ain supported her teacher's decision. She reaffirmed that she would always follow Zephyr, then joined the division with Zephyr's other students. 40

Ain later became Lin Yan's close assistant, handling meals and reporting unusual events aboard the division's ship. She was also present when the division prepared to enter the Marineford War, where Lin Yan's defense of Zephyr's past moved her to tears. 41 67 94

While traveling with Lin Yan, Ain's attachment to him became increasingly obvious. Her jealousy over Amazon Lily and Boa Hancock led to open friction with Hancock, but she and Lin Yan ultimately became a couple. 186 189 196 199

Lin Yan later used the Holy Grail of the Underworld to completely transform Ain's body. The process gave her dragon-like physical traits and dramatically elevated her combat ability beyond her former limits. 209 211

Appearance

Ain is a young woman with long, sky-blue wavy hair, pale-blue clothing, and a notably cold, vigilant expression when confronting strangers. 35

• Long sky-blue hair draped over her shoulders. 35
• Usually wears a pale-blue outfit or long dress; she considers her usual wardrobe conservative. 35 112
• Carries twin swords at her waist. 186
• Can assume an elegant blue dragon form after her Holy Grail transformation. 211

Personality

Ain is intensely loyal to Zephyr and initially treats threats to him with immediate hostility. Even after Lin Yan defeats her through genjutsu, her first concern is why he has come for her teacher. 35

She is observant and clever rather than blindly trusting. When Lin Yan gives an incomplete explanation of his past connection to Little Hancock, Ain quietly contacts Zephyr and investigates the events herself. 187

Around Lin Yan, Ain is caring but possessive. She worries about his safety, acts as his close attendant, and becomes openly jealous when other women—particularly Boa Hancock—appear interested in him. 41 186 196 Her embarrassment and affection do not prevent her from fighting fiercely when necessary. 211 224

Abilities & Skills

Backward-Backward Fruit

Ain's Devil Fruit regresses anything she touches by twelve years at a time. Its effect can be repeatedly applied until a living target regresses out of existence. 35 188

• Requires physical contact to affect a target. 188
• Can be redirected or avoided through illusion; Lin Yan caused her to strike a tree instead of him with genjutsu. 35
• Can be countered by opponents who prevent contact, such as Lin Yan using fist wind to keep her attacks away. 188
• She used the ability against Boa Hancock during their initial confrontation. 196

Swordsmanship

Ain is a trained swordswoman who fights with twin swords and had reached the Swordmaster Realm before her transformation. 186 209

• Her swordsmanship was initially beneath Mihawk's, but her transformed physical strength prevented him from freely applying his refined techniques. 225
• She can combine sword attacks with her Devil Fruit ability. 188
• Lin Yan initially underestimated her progress during their practice duel. 187

Dragon Transformation

The Holy Grail of the Underworld grants Ain the ability to transform into a blue dragon. 209 211

• Enhances her bones, muscles, stamina, reaction speed, offense, and defense. 209
• Gives her defense compared to legendary dragon scales. 209
• Allows her to control natural elements to a degree. 209 211
• Her power test caused significant destruction with a single stomp. 211
• Her transformed strength lets her catch one of Susanoo's descending blades with her bare hands. 212

Physical Strength and Elemental Combat

Following her transformation, Ain becomes a frontline powerhouse who relies on overwhelming physical force alongside elemental manipulation. 211 252

• She fought Mihawk to a standstill through brute strength despite his superior swordsmanship. 225
• She accepted a battle against Mihawk and Doflamingo to test her new powers. 224
• She brutally overwhelmed Jack the Drought and rampaged through the Beasts Pirates. 252
• Her combination of raw strength, elemental abilities, and Backward-Backward Fruit makes direct contact with her especially dangerous. 252

Equipment / Weapons / Items

• Twin swords — Her primary weapons in swordsmanship duels and combat. 186 188
• Backward-Backward Fruit — Her Devil Fruit power, allowing cumulative twelve-year regression through touch. 35 188

Relationships

• Lin Yan — Her division commander, traveling companion, and boyfriend. Ain serves closely beside him, protects him from perceived romantic rivals, and trusts him enough to accept the Holy Grail transformation. 41 189 196 209
• Zephyr — Her teacher and the person she initially follows into the Seventeenth Division. She remains deeply loyal to him and is moved by Lin Yan's defense of his dignity against the Marines. 35 40 94
• Boa Hancock — Romantic rival. Ain immediately opposes Hancock's attempt to speak with Lin Yan alone, while Hancock resents Ain's intimacy with him. 196 199 201
• Seventeenth Division — A member of the division alongside Zephyr and his former students; she also acts as Lin Yan's personal secretary. 40 54

Story Role / Major Arcs

Recruitment into the Seventeenth Division

Ain serves as Zephyr's first line of defense at his Sabaody residence, but Lin Yan defeats her with genjutsu and meets Zephyr. After Zephyr joins the Seventeenth Division, Ain follows her teacher into Lin Yan's crew. 35 40

Marineford War

Ain supports the Seventeenth Division before its intervention in the war and is emotionally affected when Lin Yan publicly defends Zephyr against the Marines' treatment of him. 67 94

Amazon Lily

Ain accompanies Lin Yan to Amazon Lily, where her jealousy over his connection to Boa Hancock becomes explicit. She confronts Hancock directly and refuses to leave Lin Yan alone with her. 186 196 201

Holy Grail Transformation

Lin Yan uses the Holy Grail of the Underworld to reshape Ain into a dragon-capable combatant. She tests her new power, discovers elemental control and dragon transformation, and subsequently seeks stronger opponents to measure herself against. 209 211 224

Later Battles

Ain battles Mihawk and Doflamingo during the all-out war, then demonstrates her transformed strength by defeating Jack the Drought and tearing through Beasts Pirates forces. 224 225 252

Trivia

• Ain's Fruit ability can make a target disappear entirely if its twelve-year regression effect is applied enough times. 188
• She discovered that Lin Yan had concealed important details about his past by independently contacting Zephyr for confirmation. 187
• The disturbance from her transformation was mistaken by others for a minor earthquake. 211