Mitsuhiko Ishibori (石堀光彦 Ishibori Mitsuhiko) is the alias taken by Dark Zagi after he possessed a TLT scientist named Hajime Yamaoka back in year 1991, 18 years prior to the start of the series.


Pre-Ultraman Nexus

Main article: Dark Zagi

Arriving in Colorado, where TLT, the Terrestrial Liberation Trust was newly formed with help from the newly arrived Visitors, Zagi possessed a TLT scientist named Hajime Yamaoka, killing his brain and turning it into an empty body for Zagi to use. He kills all of the TLT workers and scientist, with among them are Nagi's parents.

For five years while TLT was creating the division called, Night Raiders, Zagi hid as Mitsuhiko and manipulated the situation so that the power of Nexus could be strengthened to recreate his body.

Ultraman Nexus

With the appearance of the second Dunamist, he began his plans sending ever more powerful Space Beasts and the Dark Giants Dark Faust, Dark Mephisto. By the time of the third Dunamist, Zagi was left with no Dark Giants of his own to command his monster legions so he backed them up with his own dark power. After displaying his power of the Dark Field G he would codenamed Unknown Hand, due to the fact the he never physically appeared as far as TLT knew. All of these creatures were intentionally sacrificed so that the power of Nexus could increased allowing him to regain his body. Following the fall of second Mephisto, he began the last phases of his plans, having his beast Mega Flash attack a city in broad daylight, creating the fear needed to increase his power, while weakening the power of the Visitors potential barrier which limited the appearance of Space Beasts. After the destruction of Izmael, Ren Senjyu, the third Deunamist seemingly died and Nagi Saijyo became the fourth. It was then that Ishibori revealed himself as Dark Zagi. He then proceeded to tell the truth of how he destroyed the lab that included both of Nagi's parents as a small child, traumatizing her, knowing she would turn to hate space beasts like Zagi planned. Leaving a shock and wounded team, Zagi departed to Level 0, where Lethe was housed, the power of the Visitors was now too weak to stop him. There defeated Komon, Captain Wakura, and Illustrator with Nagi shortly after. Zagi proceeded to tell the Night Raiders his entire plan. After Nagi turned into Nexus, Lethe, the storehouse for all the deleted memories of Beast attack survivors and based on the body of Zagi, synchronized with Nagi's emotions and memories and consumed all the energy in her body because of her hatred, allowing Zagi to absorb this energy in turn to restore his physical body with the human form vanished.


Ishibori's transformation was done purely by will with the assistance of Lethe. When transforming his body radiated dark energy and the red lines on Zagi's body could be seen on his face while his eyes glowed red.

Powers and Weapons

  • Night Raider Training: Ishibori is a trained Night Raider being proficient in the use of their arms and machines.
  • Hacking: Ishibori was a skilled hacker.
  • Dark Ultra Powers: Ishibori also displayed other powers related to his nature as a dark Ultra, mainly flying, barriers and energy shockwaves, abilities that surpasses every Deunamist, good or evil.
    • Reflexes: Ishibori was fast enough to turn around and catch a bullet in his hand.
    • Protective Aura: When he performed that above maneuver his hand was covered in a dark blue energy that most likely protected him from harm. This same power appeared in shield form when he was being shot at.
      • Bullet Reflector: Ishibori is able to reflect and blast back the bullets shot by the Night Raiders, he does this be generating an energy field.
        • Energy Pulse: Using the same energy Zagi/Ishibori can generate a pulse of energy.
    • Dark Field G Deployment: A subspace Field deeper into the minus range than anything previously encountered, he can use in human form.
    • Remote Viewing: Ishibori most likely posses this ability or he could not have deployed his Dark Field G while he was with the Night Raiders or the times he was away from the action. He was also able to find and communicate with Mizorogi while he was another part of the base
    • Travel Sphere/Astral Projections: It is unknown if Zagi simply flash traveled or temporarily separated from his host body, given what his flash travel looked like when he was revived it was most likely he separated from Ishibori, or the wisp like form he took on was his 'Ultra Form' before his restored his body.
    • Mind Powers: Ishibori/Zagi has the same mental abilities as the visitors, mainly erasing memories.
    • Shielding: Ishibori/Zagi is capable of stopping the Visitors attack with his bare hands.
    • Halted Aging: Ishibori was actually old enough to be the parent of many of the Night Raiders but his body had not aged since Dark Zagi took it.



  • Ishibori is unique among Ultra Hosts, not just because his Ultra was the villain of his series but because Zagi had possessed a human body killing the host mind, making him less of a human host and more of a human form.
    • This is also why he doesn't qualify for the Evil Ultra Host category because he is the Ultra in question but in a different spin on the Human Form trope.
  • When Ishibori used some of his powers his eyes glowed red in a similar manner to Shunichi Maki, however when he transformed his face also sported the markings of Zagi on his body.
  • It is unknown if he was still biologically alive but given TLT's entry physical examination he either used his powers to mask his nature or he used his powers to pass as a normal human. It should be noted that Ishibori was once injured by a Space Beast like a normal human being, requiring medical attention.
  • Ishibori's actor, Kosei Kato was also a finalist to play Himeya. His actor was also aware from the start that his character would be the final villain of the series.
Human Hosts and Forms
Showa Hosts Shin Hayata | Dan Moroboshi | Hideki Go | Seiji Hokuto | Yuko Minami | Kotaro Higashi | Professor Ohtani | Shuuhei Aragaki | Tetsuya Kitajima | Tadao Nambara | Takashi Ueno | Gen Otori | Choichiro Hikari | Kyoko Kodaka | Takeshi Yamato | Ryoko Hoshi | Scott Masterson | Chuck Gavin | Beth O'Brian
Heisei Hosts Jack Shindo | Kenichi Kai | Masaki Kazamori | Genki Kagura | Mysterious Girl | Shin Kenmochi | Agent Sean | Masato Usami | Katsuto Asahi | Daigo Madoka | Tsubasa Madoka | Amui | Ikuru | Yuuto Tamaki | Kazuma Asuka | Shin Asuka | Gamu Takayama | Hiroya Fujimiya | Takeshi Yoshioka (Hyperspace) | Ginga Yumeboshi | Musashi Haruno | Julie | Shunichi Maki | Jun Himeya | Ren Senjyu | Nagi Saijyo | Kazuki Komon | Kaito Touma | Ikuo Hasunuma | Mirai Hibino | Kazuya Serizawa | Ryu Aihara | Shingo Sakomizu | Jin | Run | Shin Moroboshi | Nozomu Taiga | Hikaru Raido | Sho | Daichi Oozora | Akiko Fuji (Ultraman F) | Gai Kurenai | Riku Asakura | Leito Igaguri | Katsumi Minato | Isami Minato | Rosso | Blu | Asahi Minato
Reiwa Hosts Hiroyuki Kudo | Haruki Natsukawa | Shin Hayata (Marvel) | Kengo Manaka
Evil Ultra Hosts Keigo Masaki | Riko Saida | Shinya Mizorogi | Hiroyuki Misawa | Mitsuhiko Ishibori | Arie Ishikari | Makoto Aizen | Kirisaki
Other Hosts Takeshi Hongo | Kyotaro Kagami | Officer Sakomizu | Goro Kirishima | Yuji Hayase | Tetsuo Hayase | Lily Hayase | Daisuke Misaki | Naoki Tachibana | Koh | Ai Tachibana | Zen Tachibana | Toki Goh | Naoto Sho | Takeshi Todo | Ippei Baba | Yuka Inoue | Mai Midorikawa | Sam Collins | Ai Kumashiro | Akira Kageyama | Rei | Nao | Tomoya Ichijouji | Daisuke Misaki (Glenfire) | Amate | Yuta Hibiki | Hikari Kaizaki
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