Raiden Mei

Biodata

Feature	Value
Name	Raiden Mei (雷电芽衣)
Alias(es)	Mei
Species/Race	Human; host to the Herrscher of Thunder consciousness
Gender	Female
Affiliation	St. Freya Academy
Occupation/Role	Valkyrie trainee; Herrscher of Thunder
Status	Alive
First Appearance	Chapter 48 (mentioned) 48

Power Progression

Stage / Realm / Level	Chapter	Notes
Partial use of Herrscher of Thunder authority	60 60	Borrowed the inner Herrscher's power to strike a simulated Honkai Emperor's core after being overwhelmed; Yomi adjusted the device limiting her power.
Approximately 30% authority mastery	89 89	Following a clash with the Herrscher of Thunder, she could access roughly thirty percent of its authority and considered herself comparable to an A-rank Valkyrie in armor.
Near S-rank Valkyrie baseline	105 105	Repeated Elysium Everlasting trials raised her strength to nearly the minimum standard of an S-rank Valkyrie.
Flame-Chaser Signets acquired	107–108 107 108	Cleared the Annihilation trial and received Kalpas's Signets after previously progressing through Infinity and Salvation.
First Ascension	133 133	Mei and the Herrscher of Thunder completed their Ascensions simultaneously. With the Sin Mallet Thunder of Seven and fourth-generation Godkiller Armor, she could contend with normal Durandal and potentially Durandal's Luna Kindred state.
First Ascension, limited utilization	134 134	Despite her new level, she could use only about twelve percent of her power; she believed full utilization would let her reach Durandal's current level.

Background / History

Raiden Mei is Raiden Ryoma's daughter. Genetic analysis initially identified Yomi as Mei's daughter despite the two appearing to be the same age; Yomi's greater genetic differentiation complicated the apparent timeline of their relationship 48.

At St. Freya Academy, Mei met Yomi as a new teacher and was unsettled by their resemblance and immediate sense of familiarity. Her initial hostility became a desire for closeness, and she asked to call Yomi her sister before learning the truth of their blood relation 54 57 86.

Mei possessed the Herrscher of Thunder within her, but a device bomb restricted her access to its authority. After nearly losing to a simulated Honkai Emperor, she drew on the Herrscher's power to destroy its core. Yomi subsequently adjusted the restraint device and offered protection should the inner consciousness threaten Mei 60.

Yomi became Mei's principal combat mentor, providing detailed swordsmanship instruction, combat notes, a protective flower, and the custom fourth-generation Godkiller Armor Thunder Knight: Moonbeam 65 67 91. Mei later entered Elysium Everlasting, where repeated near-fatal trials against Flame-Chaser simulations strengthened her connection with the Herrscher of Thunder 95 102 103.

Pink Elf eventually revealed that Yomi was Mei's biological daughter, with Mei and Elysia as Yomi's biological parents. Mei struggled with the revelation before accepting her role as Yomi's mother; Yomi later confirmed that she was both Mei's daughter and older sister 106 109 110.

When Yomi's domain destabilized under Honkai corruption, Mei entered it with a sword containing Yomi's former authority. She was forced to stab Yomi, returning that authority to her body and triggering Yomi's struggle against the invading consciousness 108 109.

Appearance

Mei closely resembles Yomi; Kiana remarks that they would look completely like sisters if they styled their hair alike 60.

• Purple eyes that can flash with electricity when she invokes Herrscher power 133.
• Wears a practical combat uniform at St. Freya; hers was once identical in style to Yomi's 60.
• Uses the custom Thunder Knight Godkiller Armor for dangerous combat and Elysium trials 91 95.

Personality

Mei is intensely protective of the people she considers her own. Rather than being driven by abstract ideals such as saving the world, she prioritizes protecting specific individuals, particularly Yomi, Kiana, and Xiao Qi 149.

Her personality changed as she gained greater control over the Herrscher of Thunder's authority. Once a more domineering young lady, she became timid after later hardships and the influence of the Gem of Conquest, but gradually began to reclaim and accept her former assertiveness 132.

Mei is deeply possessive toward Yomi and becomes jealous when others receive Yomi's attention. Her attachment initially takes the form of a sister complex, then becomes more complicated after learning that Yomi is her daughter 87 91 120. She is also capable of restraint and resolve, enduring Elysium's trials and accepting painful choices when Yomi's life is at stake 89 109.

Abilities & Skills

Herrscher of Thunder Authority

Mei shares a body with the Herrscher of Thunder, a separate consciousness that initially protected her unilaterally. Their connection grows through combat and Elysium's trials.

• Can channel lightning through her sword to destroy Honkai Beast cores 60.
• Reached roughly thirty percent mastery of the authority before entering Elysium Everlasting 89.
• Her lightning gained strong penetrative force after First Ascension 136.
• Overpowered the Herrscher of the Void in close combat by exploiting the weakness of spatial bindings at point-blank range 136.
• Her power remains limited by incomplete utilization; after First Ascension, she could only employ about twelve percent of it 134.

Swordsmanship

Mei is a sword user trained extensively by Yomi.

• Received close, comprehensive instruction focused on correcting every identifiable weakness 65.
• Used swordsmanship and Herrscher power to survive prolonged Elysium trials against Kalpas and Mobius 95 102.
• Challenged Durandal during the Rank B Valkyrie examination and lasted far longer than expected, though she was defeated 133 134.

Ascension and Metamorphosis

Yomi established a metamorphosis system for both Mei and the Herrscher of Thunder.

• The Sword of Damocles hangs over both consciousnesses, requiring Mei to retain her sense of self and the Herrscher personality to withstand the descending sword 111 112.
• A second metamorphosis requires the Herrscher of Thunder to accept Yomi's full-power conscious strike, making it far more dangerous than the first 112.
• Mei completed her First Ascension alongside the Herrscher of Thunder after the latter endured an Ascension trial 133.

Equipment / Weapons / Items

• Thunder Knight: Moonbeam — Custom fourth-generation Godkiller Armor tailored specifically for Mei. It protected her from Elysium's cold and greatly augmented her combat strength 91 95 133.
• Sin Mallet Thunder of Seven — God Key sword previously wielded by Yomi. Mei cannot yet unleash its rated power, but it substantially improves her combat ability 110 133.
• Protective flower — Given by Yomi to protect Mei in Yomi's stead 67.
• Yomi's swordsmanship notes — Instructional notebook containing Yomi's combat insights 67.
• Sword of Damocles — A consciousness-bound instrument of metamorphosis designed by Yomi 111 112.

Relationships

• Yomi — Her biological daughter and older sister. Mei first regarded Yomi as a teacher and sought to call her sister; after learning the truth, she accepted being Yomi's mother 57 65 106 110.
• Elysia — Yomi's other biological mother. Elysia oversees Mei's Elysium trials, teases her relentlessly, and remains a close but complicated companion 103 107 120.
• Herrscher of Thunder — Mei's inner Herrscher consciousness. Initially fearful of Yomi, she protects Mei and eventually completes First Ascension alongside her 86 133.
• Kiana — Mei's closest friend and a person she deeply cherishes. Their relationship is strained by the Herrscher of the Void's impersonations and Mei's conflicted feelings 57 136 157.
• Xiao Qi — A child who recognizes Mei as her mother. Mei becomes determined to protect her and reunite her with Kiana 133 135 142.
• Raiden Ryoma — Mei's father. Her former dependence on him fades into resentment and indifference after Yomi's arrival and the revelation of Yomi's identity 84 87 120.
• Durandal — A powerful rival Mei challenges to prove her growth. Mei loses their spar but uses it as motivation to pursue a second Ascension 133 134.
• Xianna — An overwhelmingly stronger opponent whose appearance exposes the limits of Mei's current power and drives her further growth 165.

Story Role / Major Arcs

St. Freya Academy and Yomi's Arrival

Mei meets Yomi, initially distrusts her closeness with Kiana, and becomes increasingly preoccupied with their shared appearance and blood connection. Yomi trains Mei, loosens the restraint on her Herrscher authority, and provides equipment intended to help her become self-reliant 57 60 65 67.

Elysium Everlasting Trials

Mei enters Elysium Everlasting to obtain strength and Flame-Chaser Signets. She faces dangerous trials under Kalpas and Mobius, repeatedly confronting near-death conditions that deepen her bond with the Herrscher of Thunder 95 102 103 107.

Yomi's Corruption Crisis

After learning that Yomi is her daughter, Mei joins Kevin's attempt to save her from Honkai corruption. Mei enters Yomi's domain, returns Yomi's former authority by stabbing her, and accepts the painful reality of their mother-daughter relationship 106 108 109 110.

First Ascension and Durandal Challenge

Following Yomi's departure for the Land of Origin, Mei completes First Ascension and challenges Durandal in the Rank B Valkyrie examination. Though defeated, she proves capable of facing Schicksal's strongest Valkyrie for an extended fight and resolves to become strong enough to protect those she loves 133 134.

Xiao Qi and the Herrscher of the Void

Mei comes to accept Xiao Qi as her daughter while confronting the Herrscher of the Void's manipulation of Kiana's identity. She defeats the Void Herrscher in close quarters once, but is later deceived into surrendering the Sin Mallet Thunder of Seven and submitting to protect Kiana and Bronya's family 136 142 153 154.

Xianna's Threat

When Xianna appears with multiple Herrscher authorities, Mei is unable to oppose her directly. The confrontation makes clear that, without the Herrscher of Thunder's power, Mei is only an ordinary S-rank Valkyrie against Xianna's overwhelming strength 165.

Notable Quotes

“I, Raiden Mei, will definitely defeat Finality, no matter the cost!” 133