Aka Akatsuki

Biodata

Feature	Information
Name	Aka Akatsuki (晓古城)
Alias(es)	Fourth True Ancestor
Species/Race	True Ancestor vampire
Gender	Male
Affiliation	Saikai Academy
Occupation/Role	Student; Fourth True Ancestor
Status	Alive 226
First Appearance	Chapter 180

Power Progression

Stage / Realm / Level	Chapter	Notes
Unacknowledged Fourth True Ancestor	180	Bronya identifies him as a late bloomer whose Beasts of the Lord have not yet acknowledged him.
Access to Lion of Gold	184	Borrows golden lightning from Lion of Gold in battle, but cannot properly summon it; the Beast later riots after he is injured.
Crimson Horns available	195	Uses Crimson Horns alongside Lion of Gold against Naraku Viller, though the two Beasts cannot destroy its commander unit.
Several additional Beasts awakened	216	Byakuya senses that Aka has awakened several more Beasts of the Lord after feeding.
Aries Diamond awakened	222	Uses Aries Diamond to form a crystal barrier against the Dragon Beast's magic barrage; the same Beast later automatically deflects a spatial tail strike.
Multi-Beast coordination	226	Summons Dragon-Snake's Mercury, Lion of Gold, Crimson Horns, and other Beasts together against the Dragon Beast, showing substantially improved control.

Background / History

Aka attends Saikai Academy while attempting to live as an ordinary student. His close friend Yase Motoki knows his identity and serves as his overseer, while Aka himself initially remains inexperienced and uncomfortable with the responsibilities of being the Fourth True Ancestor. Bronya exposes his identity after assessing his power as merely average. 180 181

His early combat record reflects this inexperience: he cannot freely summon his Beasts of the Lord, struggles against basic illusions and artificial life forms, and repeatedly relies on Kishiryu Yukina or Byakuya during crises. 184 186 194

Personality

Aka is initially hesitant and self-conscious about his position as the Fourth True Ancestor. He repeatedly views himself as a normal high-school student and is shaken when stronger figures dismiss him as half-baked or weak. 189 212

Despite this insecurity, he is protective and stubbornly determined. He intervenes to protect Yukina, Astarte, Yuma Sendou, and Aoba Asagi even when he knows he is outmatched. His willingness to take a fatal blow for Yukina marks a major shift from passive insecurity toward self-sacrifice. 186 187 195

Byakuya's harsh training gradually improves Aka's confidence and combat awareness. Though he complains about the training, he later reads Amatsuka Kou's movements, dodges his attack, and counters effectively. 196 216

Abilities & Skills

True Ancestor Physiology

As the Fourth True Ancestor, Aka possesses exceptional magic power, vampiric regeneration, and an immortal body.

• His blood can return to his body after injury, rapidly restoring him. 184
• He survives a fatal blow during the confrontation with Rudolf and revives shortly afterward. 187
• His Beasts of the Lord can react independently to threats, including showing wariness toward Byakuya. 185
• His immortality does not compensate for poor control: early in the story, he cannot reliably summon or command his Beasts. 180 184

Beasts of the Lord

Aka's primary weapons are the Beasts of the Lord sealed within him. Their awakening and cooperation determine much of his fighting ability.

• Lion of Gold — manifests golden lightning for melee attacks and large-scale lightning strikes. 184 194
• Crimson Horns — one of the additional Beasts he can deploy against Naraku Viller. 195
• Aries Diamond / Divine Ram's Diamond — generates a crystal barrier that blocks magical bombardment and automatically protects Aka from lethal attacks. 222 226
• Dragon-Snake's Mercury — deployed alongside his other Beasts during the Dragon Beast battle. 226
• His early limitation is a lack of synchronization; he initially has only Lion of Gold available and cannot use useful abilities such as Silver Mist of the Shell when needed. 194

Hand-to-Hand Combat

Byakuya trains Aka in the Mirror World to correct his weak physical foundation and overreliance on Beast of the Lord powers.

• Training emphasizes close-quarters combat rather than raw magic power. 196
• Byakuya heals Aka's injuries after each session with White Flower. 196
• The training allows Aka to evade Amatsuka Kou's mercury blade and land a clean counterpunch. 216

Relationships

• Kishiryu Yukina — His Lion King Organization Observer and closest combat partner. Aka repeatedly protects her, while Yukina shields and supports him when his powers fail; their bond deepens after he sacrifices himself for her. 184 187 226
• Byakuya — A vastly stronger mentor and informal rival. Byakuya suppresses Aka's rampages, defeats him in sparring, and trains his hand-to-hand combat while relentlessly criticizing his lack of control. 185 189 196
• Bronya — The first person to directly confront him about being the Fourth True Ancestor. She challenges his weakness, later provides Yukina with an improved Snowfall Wolf, and arranges the Dragon Beast battle to test Aka's growth. 180 226
• Nangong Natsuki — A mentor and authority figure who monitors Aka's actions and warns him about the dangers surrounding a half-developed True Ancestor. 186 192
• Yuma Sendou — His childhood friend. Aka remains concerned for her during the body-swap and Prison Barrier incidents, refusing to abandon her after learning how Aya Sendou treated her. 209 211 212
• Aoba Asagi — A school friend who becomes trapped during the Foundation Gate attack; Aka immediately prioritizes locating and helping her. 187
• Yase Motoki — His close friend and secret overseer, aware of Aka's true identity. 180
• Akatsuki Reika — His future daughter. Their first present-day meeting is strained because Reika impersonates Yukina and conceals her identity. 221 222

Story Role / Major Arcs

Saint's Right Arm Incident

Aka's first major crisis as the Fourth True Ancestor begins with Rudolf Ostach and Astarte. He initially cannot summon a Beast of the Lord properly, is overwhelmed by Astarte, and triggers Lion of Gold's rampage before Byakuya contains the disaster. 184 185

After Rudolf attacks the Foundation Gate, Aka takes a fatal strike to protect Yukina and later confronts Byakuya when he attempts to take Rudolf and Astarte away. His challenge ends in a decisive defeat in Byakuya's Mirror World, forcing him to recognize how weak he remains. 187 189

Black Death Emperor Faction and Naraku Viller

Aka investigates the Black Death Emperor Faction with Yukina and Asagi. During the Naraku Viller attacks, he struggles against machines that can adapt to Lion of Gold's lightning, but continues fighting alongside Yukina and Sayaka. 192 194

He unlocks and uses additional Beasts, including Crimson Horns, but Byakuya ultimately has to remove him from the battlefield and destroy the commander unit himself. 195 196

Prison Barrier Incident

Yuma Sendou swaps bodies with Aka to break the Prison Barrier. Trapped in Yuma's body and hindered by spatial distortions, Aka persists in pursuing her with Yukina's help. 210 211

After reaching the Prison Barrier, he protects Yuma from Aya Sendou and tries to intervene in the conflict, only for Byakuya to remove him from the battlefield because he is still too weak. 212

Amatsuka Kou Conflict

Aka's training pays off when Amatsuka Kou attacks him. He recognizes the alchemist's hostile intent, avoids his mercury blade, counters in close combat, and works with Yukina and Mana to pressure him into retreating. 216 217

Dragon Beast Battle

After Reika's arrival from the future, Aka faces a Dragon Beast that threatens String God Island's magic power. He initially relies on Aries Diamond to survive, then later summons multiple Beasts of the Lord in coordination with Yukina and Reika to defeat it. 222 226

Notable Quotes

“I'm telling you, Kishiryu, don't underestimate me too much. I'm not that weak.” 222

“Then, the next part is my fight.” 226