Yukina

Biodata

Feature	Information
Name	Shiomi Yukina (雪奈)
Alias(es)	Fifina
Species/Race	Human
Gender	Female
Affiliation	Youcheng Girls' Academy; Orderkeepers Organization, Third Group 1 118
Occupation/Role	Student council officer; Magical Girl/Agent; long-range combat support 1 76 118
First Appearance	Chapter 1 1

Power Progression

Stage / Realm / Level	Chapter	Notes
First Synchronization	19 21	Confronting an Erosion Entity during the sports-arena disaster triggers a silver pillar of light and her first transformation.
Absolute Compatible Candidate	47 49 50	Medical testing identifies her as an unusually rare candidate with broad Beacon compatibility and unknown potential.
Prospective Agent — “Fifina”	72	Accompanies Efnir into operations under the Fifina codename.
Official Agent, Third Group	114 118	Formally registered as an Agent and assigned under Efnir’s command structure.

Background

Yukina was raised by the Yanase family after losing her biological parents at a young age. She retained the Shiomi surname and calls Yanase Naoko’s parents “Uncle” and “Aunt.” 157

As a child, she was exceptionally close to Yanase Naoto, whom she believed to be her older brother. Their relationship became distant when Naoto’s Agent work, public duties, and efforts to keep Yukina away from the Orderkeepers’ world left them with little time together. 1 2

During an Erosion Disaster at a sports arena, a hooded girl led Yukina out of the shelter through a secret passage. Finding her brother’s phone and facing an Erosion Entity pushed Yukina into panic and awakened her first Synchronization. 19 21

Yukina later learned that Efnir was Naoto’s true identity and that Naoto had been living as a woman while acting as the city’s chief Agent. Though initially confused and hurt by the deception, Yukina chose to rebuild their relationship rather than leave Efnir alone. 31 32 33

Appearance

In daily life, Yukina is a slender, graceful high-school student with black hair and a silver butterfly hairclip. She is taller than Efnir’s Exile Form and is noted for her refined, reserved appearance. 15 53 125

• Her hair becomes aqua-blue while synchronized. 75 125
• Her Agent attire is an aqua dress resembling ice, snow, and flowing water. 75
• Her Order Weapon is a heavy, crystal-like longbow. 75
• She carries a silver butterfly hairpin that is also the Beacon connected to her transformation. 19 260

Personality

Yukina is quiet, reserved, and initially uncomfortable forming close relationships. Kanade Kotone is one of the few friends she makes in high school, while Yukina herself recognizes that she is not naturally good at opening up to others. 43 104

She is academically gifted but was originally poor at sports and easily exhausted by physical exertion. After becoming an Agent, she approaches training with stubborn determination, repeatedly pushing herself to catch up to Efnir despite the pain and the obvious difference in their experience. 46 107 125 127

Her devotion to Efnir is central to her decisions. Yukina can be reckless when Efnir is in danger, as shown when she jumps toward a departing helicopter to follow her, but she steadily develops into a composed combatant capable of analyzing enemies and making tactical decisions under pressure. 70 185 188 190

Abilities & Skills

Synchronization and Order Force

Yukina’s Synchronization grants her enhanced physical capabilities, sharpened senses, and an Agent combat form.

• Her eyesight becomes precise enough to read distant text from across the school grounds. 45
• Her physical strength and sensory abilities rose rapidly after her first Synchronization. 44 45
• She possesses exceptionally high compatibility and adaptability with Order Force. 49 121
• Her stamina, oxygen control, and sustained Order Force management remain major weaknesses during prolonged combat. 107 181

Longbow and Arrow Attacks

Yukina’s Order Weapon manifests as a crystal-like longbow that fires high-output aqua-colored arrows.

• Her arrows can pierce an Erosion Entity’s limb and the structure behind it in a single shot. 76
• She excels at long-range support, battlefield observation, and targeting enemies from elevated positions. 76 79
• A focused arrow strike can shatter an Apostle defensive barrier. 183
• Her instantaneous output has been compared to Kite’s amplified attacks; each arrow carries exceptional penetration and destructive force. 157
• Her effectiveness falls sharply in close-quarters combat or when exhausted. 76 134 190

Stairway

Yukina can create temporary footholds in midair through the Agent technique known as Stairway.

• Learned the basics rapidly during her early Agent training. 121
• Uses Stairway for aerial mobility, evasive maneuvers, and climbing during combat. 185 189
• Her use is less refined than that of veteran Agents. 121 181

Firearms and Tactical Training

Under Efnir’s instruction, Yukina trains in firearms, maintenance, tactical movement, first aid, climbing, vehicle operation, and other Agent support skills. 120 123

• Scored 8.92/10 in her first firearms session. 121
• Demonstrated rapid understanding of handgun use, maintenance, archery, and Stairway training. 121
• Uses deception and battlefield misdirection, including smoke grenades and an Efnir mannequin decoy, to evade Apostle pursuit. 185 188
• Has learned emergency battlefield medical treatment from Nishizaki Yuki. 149

Combat Instinct

Despite limited experience, Yukina displays unusual battlefield awareness.

• Instantly deduced the directions of incoming gunfire during the relay-station battle. 181
• Maintained composure while injured and pursued, drawing Apostles away from Efnir through calculated feints. 185 188 190
• Her lack of close-combat experience remains exploitable against skilled melee opponents such as Hatsukawa Fuka. 190

Equipment / Weapons / Items

• Silver butterfly hairpin — A Beacon brought to Yukina by Codename H; it is closely tied to her first Synchronization. 19 260
• Crystal-like longbow — Her manifested Order Weapon. 75
• Agent Terminal and subsidy card — Issued upon joining the Orderkeepers. 119
• Enhanced Agent handgun — Used during firearms training; Efnir also entrusts her with a pistol during her first operation. 76 120

Relationships

• Yanase Naoko / Efnir / Yanase Naoto — Yukina’s foster sibling and former “older brother,” later revealed to be Efnir. Their relationship evolves from estranged siblings to romantic partners; Yukina trains and fights to stand beside her. 31 58 114 127
• Kanade Kotone — Yukina’s best friend and one of her few close school acquaintances. Kotone supports Yukina’s plans for Naoko’s birthday and engagement gift. 43 225 227
• Nishizaki Yuki — Orderkeepers physician who examines Yukina’s unusual condition, identifies her exceptional compatibility, and later teaches her battlefield medical treatment. 47 49 149
• Masaki Hina — Orderkeepers commander who approves Yukina’s formal registration and places her under Efnir’s command. 115 117 118
• Uzuki Saori — A senior Agent who saves Yukina during the Maesakagawa conflict. Yukina views her primarily as someone who protected both her and Efnir. 187 231
• Yanase family — Her foster family. Yukina was raised in their home and considers their life together the foundation of her childhood. 53 157

Story Role / Major Arcs

Sports Arena Erosion Disaster

Yukina escapes the shelter with help from a hooded girl, witnesses Efnir fighting Erosion Entities, and undergoes her first Synchronization after confronting the disaster directly. 19 21

Efnir’s Identity Reveal

She learns that Efnir is Yanase Naoto, the sibling she had known as her older brother. The revelation forces Yukina to reconsider her memories, her resentment, and her feelings toward Efnir. 31 32 33

First Field Deployment

As prospective Agent Fifina, Yukina follows Efnir into an emergency operation. She performs her first high-altitude insertion, manifests her bow, and acts as Efnir’s long-range observer and support. 72 75 76 79

Formal Agent Training

After choosing to become an official Agent, Yukina joins the Third Group and trains under Efnir. Her rapid progress reveals exceptional aptitude, though her eagerness repeatedly drives her past safe limits. 114 118 121 125 127

Battle Against Codename H

Yukina confronts a Dog-type Erosion Entity and later attacks Codename H to protect an injured Efnir. The fight exposes the gap between training and real combat, but Yukina’s arrow barrage weakens H’s defenses and creates openings for Efnir. 134 135 136

Maesakagawa Recapture Operation

During her second official operation, Yukina supports Anilas and Kite against Erosion Entities. Her timing, precision, and destructive output impress veteran Agents despite her inexperience. 155 157 170

Relay Station Siege

Yukina fights through exhaustion and severe injuries to rescue Efnir from Apostle forces. She uses decoys, misdirection, precise archery, and coordinated attacks with Efnir to survive the encirclement and help force the Apostles’ retreat. 181 183 185 188 191

Notable Quotes

“As long as I'm with Naoko, I'm not afraid of anything.” 114

“When it comes to loving someone, I have the confidence that I won't lose to you, Naoko.” 192