Asuna Yamase

"Take over the universe? Stick to obnoxious outfits, not obnoxious plots. I'm not letting that happen."

―Asuna, to Gina Spectre

Asuna Yamase
Data
Type	Ally
Gender	Female
Age	19 years old
Family	Unnamed Father Unnamed Mother
Affiliation	Xio
First Appearance	Ultraman X episode 1 "A Voice From the Starry Sky"
Latest Appearance	Ultraman X The Movie: Here He Comes! Our Ultraman
Portrayed by	Akane Sakanoue Elise Napier (English Dub)

Asuna Yamase is one of the main characters of Ultraman X. She is a member of Xio.

History

Pre-Ultraman X

Asuna's first appearance.

From a young age, Asuna trained rigorously in sports—especially swordsmanship and gymnastics—under her family's guidance. But in middle school, she dreamed of becoming a model and became fascinated with fashion magazines. Her perspective changed after a kendo match where she defeated her first love. The emotional loss led to their breakup and left her questioning herself. Frustrated, she wondered why she couldn't live a normal life like other girls. From then on, she believed, "If girls can't live ordinary lives, something's wrong with the world."

The summer before high school, kaiju attacked her city. Her father, a police officer, was injured while helping evacuate civilians. Though her mother urged him to quit, he insisted on protecting others, even at personal risk. Inspired by his resolve and worried for him, Asuna made her own choice: "If someone has to do it, then I will."

She gave up modeling and joined the Xio Prep Squad. Still, she craved a normal high school life, enjoying vacations and even a brief romance while working at a mountain lodge.

In a later TV interview, Asuna said part of her motivation was to prove protecting Earth shouldn't be just men's responsibility. She admitted that if she hadn't joined Xio, she might have just become "a regular college student living an ordinary life." ^{Feature Report! 24 Hours Inside Xio}

Ultraman X

In the series, Asuna and Daichi participate in missions as partners.

After graduating from her local high school, Asuna joined Xio as a trainee and quickly rose through the ranks to secure a key role on the elite Special Search Team. Her outstanding skills and dedication earned her the position of Daichi Oozora's "bodyguard" and partner. At first, she was skeptical of Daichi's idealistic vision of peaceful coexistence between humans and kaiju and was often frustrated by his tendency to go it alone. However, she genuinely cared about his well-being, often showing more concern for him than anyone else on the team, both during and outside of battle. Asuna shares a close friendship with Rui Takada, probably because they are around the same age. The two often joke with each other, with Asuna playfully mimicking Rui's expressions and catchphrases.

Asuna witnesses Ultraman X's first appearance.

In the early episodes, Asuna takes part in a mission to stop the kaiju Demaaga, who is wreaking havoc with a devastating heat ray. During the chaos, she becomes separated from Daichi. Just as things grow dire, a giant figure appears. Despite the danger, Asuna continues searching for Daichi. When Demaaga targets her, the giant intervenes and protects her. Recognizing the giant as an ally, Captain Shotaro Kamiki orders the team to provide support. With their help, the giant defeats Demaaga using the Xanadium Beam, reverting the monster into a Spark Doll. From then on, the figure is known as Ultraman X. ^{A Voice From the Starry Sky}

Later, Asuna and Daichi investigate a series of small earthquakes near an underground construction site. There, they meet a mysterious woman wearing sunglasses. When she makes a strange sound, the kaiju Telesdon emerges from below. Following protocol, Xio deploys its ground combat machine, the Xio Musketty, which combines with Asuna's vehicle, the Xio Porthos, to form the Land Musketty. Asuna fires the powerful Fanton Rail Cannon, but Telesdon escapes.

Asuna told Daichi about her past and her wish to be more feminine.

They later discover the woman is Ryoko Mabuse, a former beauty salon owner who died in an accident two months earlier. To learn more, Asuna and Daichi go undercover as a couple. When Ryoko realizes this, she attacks and knocks Daichi out. Asuna chases her but is shot at. Though unharmed, her new high heels are ruined, letting Ryoko escape. Vice-Captain Sayuri Tachibana later scolds Asuna for wearing inappropriate shoes on the mission. Asuna tells Daichi she values her femininity because of her past and isn't ready to give it up.

That night, another quake hits. Asuna and Daichi encounter Ryoko again. Pointing to the city lights, Ryoko says, "Humans are trying to take the night from us," then summons Telesdon, who attacks the city. Daichi merges with X but struggles. Just in time, Xio arrives and deploys their new weapon, the Ultlaser, to support him. X then equips the Eleking Armor, a kaiju-based upgrade, and defeats Telesdon, saving the city. Ryoko attacks Asuna again but vanishes after the Xio team counters. Days later, Asuna celebrates her birthday, and her teammates gift her a new pair of high heels. ^{A Song That Calls the Night}

During a mission to confront Demaaga's second appearance, a mysterious energy from space caused the creature to evolve into Tsurugi Demaaga. At the same time, X was exposed to this energy, which destabilized his body and left him severely weakened. Asuna and her team arrived to investigate but encountered a mysterious woman named Gina Spectre. She revealed she had harnessed the energy to enhance Demaaga in her quest to conquer the universe. Shortly after, Gina summoned Zaragas from a Spark Doll and vanished.

Asuna called for backup from Xio, but before help arrived, Tsurugi Demaaga reappeared in the city, worsening the crisis. Dr. Gourman suggested using Daichi's Gomora and gave Asuna a Cyber Card. Although it was uncertain if she could control Cyber Gomora, the summon succeeded. Asuna battled Zaragas and defeated it using the Cyber Ultra Vibration Wave, reverting it to a Spark Doll. ^{End of the Rainbow}

Asuna and Arisa work together in battle.

When members of the UPG were transported into X's world, Asuna formed a friendly bond with Arisa Sugita. With their shared skills in hand-to-hand combat and similar ages, they quickly became a strong team. Together, they supported X, Victory, and Ginga in their fight against Mold Specter. Observing them in action, Hayato and Wataru remarked that the two gave off a similar energy. ^{Sword of VictoryThe Shining Sky, and the Land Beneath It}

During a Xio test to materialize Daichi's Gomora from a Spark Doll, a protective barrier was set up to guard against potential surges of Dark Thunder Energy from the unstable monster. The test had a strict three-minute limit. Within that time, Gomora successfully materialized and responded to Daichi's commands, showing clear communication. But when the timer ended, a surge of Dark Thunder Energy breached the barrier, causing Gomora to mutate into EX Gomora and go berserk. Daichi transformed into X to stop it but was quickly captured by M1.

Asuna saw Gomora rampage and tried to wake it without hurting it.

As EX Gomora rampaged, Xio decided to eliminate it. Watching coldly, M1 warned that humanity's failure to coexist would lead to extinction. Refusing to accept this, Asuna bravely pleaded with EX Gomora to stop. Despite being nearly trampled and injured, she persisted. Moved by her resolve, EX Gomora's horns began to glow. M1 then snapped his fingers, returning X to the battle. X shielded Asuna with the X Barrier Wall and used the "Exceed X Slash" to subdue EX Gomora, reverting it to its original form. ^{Living Together}

After hearing what he believed was his missing mother's voice, Daichi investigated a research facility linked to a temporal anomaly. Driven, he worked nonstop for three days, worrying Asuna, who urged him to rest. Meanwhile, Xio received a report from UNVER's Geneva headquarters confirming Dark Thunder Energy near the solar system—a force known to trigger extreme aggression in monsters. Reviewing footage from Wataru and Mamoru Mikazuki's lunar patrol, Xio discovered that the glowing entity captured was caused by a human brain forced to perceive "nothingness," explaining why the source of Dark Thunder Energy was untraceable. The entity soon attacked and destroyed UNVER's Nevada branch.

Asuna sees Daichi become X.

X contacted Xio through Daichi's X Devizer, identifying the entity as Greeza—a creature that absorbs all biological energy on a planetary scale, reducing it to nothingness. It was revealed that the Ultra Flare incident 15 years ago resulted from a battle between X and Greeza. With Greeza heading to Operation Base X, where many Spark Dolls were stored, X called for Xio's full cooperation. A joint strike was launched, but Greeza broke through and landed in Japan. Realizing the urgency, Daichi merged with X in front of Asuna. Shocked, she revealed to the team that Daichi was X.

Greeza's intangible form made X's attacks ineffective. Daichi and X tried a desperate internal assault. Although Greeza exploded, only X's color timer remained. Asuna touched the timer and heard Daichi's heartbeat, confirming they were both alive. Dr. Gourman proposed sending someone into X's cyberspace to rescue him.^{A Beautiful End}

Asuna's mind enters X's cyberspace.

Asuna volunteered for the mission. Though severely damaged, Greeza began regenerating and resumed its rampage. While the Xio team worked to slow it down, Asuna's consciousness was transferred into X's cyberspace to search for Daichi. During her search, she found the Xlugger but couldn't locate Daichi. In a quiet moment, Asuna admitted her feelings—she had always thought it was her duty to protect him, but realized he had been protecting her all along. Inspired by his unwavering will, she vowed to fight with him for a future where humans and kaiju coexist. Even as her brainwaves reached critical levels, she refused to give up.

With Xlugger's power, Asuna and Daichi met again in cyberspace.

Moved by her words, Daichi responded. With the Xlugger's help, they reunited in cyberspace. Drawing strength from their bond, Daichi accessed X's memories and emotions, reigniting X's power. Revived, X returned to battle. Supported by Xio, he destroyed Greeza's core, freeing the kaiju trapped inside Spark Dolls. The kaiju merged with X, creating the powerful Hybrid Armor. In this form, X deflected Greeza's attacks and fired the Ultimate Xanadium Beam, delivering the final blow.

After the battle, Asuna and Daichi reunited. Together with Xio, they began rebuilding their base and looking toward the future. ^{The Rainbow Land}

Powers and Weapons

• Peak Human Condition: Asuna is a skilled martial arts practitioner due to her past being taught self defense by her father.
• Piloting: Asuna is a skilled driver in heavy vehicles like Xio Porthos and Land Musketty.

Gallery

Ultraman X

Ultraman X The Movie: Here He Comes! Our Ultraman

Miscellaneous

Asuna Kicking Alien Zarab

Trivia

• In an interview, Akane Sakanoue recalled feeling that the six-month filming schedule would be long. One of her most memorable moments was on the third day, during an explosion scene where she had to run as it went off behind her. After practicing the running motion repeatedly, she struggled to run smoothly, but in the actual take, she completed it in one shot. The exhaustion and breathlessness seen in the scene were her real reactions, not just acting.
• Sakanoue, who practiced taekwondo with her brother during her childhood, was praised by Hiroyuki Okano, the action director for the series, for her impressive kicking technique during filming.
• During the filming of the series, since Sakanoue had not yet obtained her driver's license at the time, all scenes involving driving were performed by a stunt double.
• In the series, Ultraman X often makes unintended but poorly timed comments regarding Asuna's weight, age, and diet.