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Thunder Killer (サンダーキラー Sandā Kirā) is a Kaiju from Ultraman Geed. This monster is made by combining Ace Killer and Eleking.

Subtitle: Belial Fusion Monster (ベリアル融合獣 Beriaru Yūgō-jū)[1]


Ultraman Geed

Thunder Killer first appeared at the end of episode 5 of Ultraman Geed where he was formed when Kei Fukuide used his Riser to turn into this monster via the Kaiju Capsules of Eleking and Ace Killer. The monster spent his time rampaging throughout the city and destroying property with his Light Blades, was met with opposition by Ultraman Geed, and the two of them immediately charged at each other.

As the two giants raged on, they were initially evenly matched, but Geed hurt his hands after he tried to hit Thunder Killer on the head, leading to the latter to strike at the former hard with his electrified talons. Afterwards, Geed transformed into his Solid Burning form in hopes of turning the tide in his favor, and he did so by attaching the Geed Slugger to his arm after Thunder Killer deflected his Psychic Slugger, but when Geed fired his Strike Boost, Thunder Killer absorbed the attack and fired it right back at him. Just when things were looking bad for Geed, Ultraman Zero appeared to give him a helping hand, only for the fusion Kaiju to vanish.

Eventually, Thunder Killer returned in Area J of Unno and so did Geed who showed up for a rematch. Their rematch started after the fusion Kaiju taunted the Ultra, which proved to be a big mistake for the former as the latter learned from their last fight and held the upper hand over Thunder Killer via combat until the Kaiju fought back and landed a reversed Thunder Discharge on him, knocking him down, and making his Color Timer go off. Riku Asakura then remembered some inspiring words said by Leito Igaguri about fate and caring about others, got back up, and for the first time, summoned his Geed Claw. With it, he landed a Claw Cutting attack on Thunder Killer then transformed into his Acro Smasher form as he dodged and deflected Light Blades with relative ease. After getting in four devastating slashes on the fusion kaiju, Geed destroyed him with his Diffusion Shower.

That wasn't the last of Thunder Killer, however. After Zaigorg defeated Dada and his personalized Legionoid, Kei used his Kaiju Capsules and Riser to transform into Thunder Killer once again. The two of them soon faced off against Geed again and throughout the fight, Geed managed to hold his own against the two Kaiju with his experience, skill, and athleticism at first, even though they outnumbered him. However, the two of them ganged up on Geed and held on him on the ropes with their teamwork. In order to stack up to their levels, Geed transformed into his Royal-Mega Master form.

While he was in this form, Geed was able to hold both Kaiju at bay with his sword while swiftly and majestically dodging their attacks. After defeating Zaigorg, Geed turned his attention towards the chimera Kaiju and once again managed to overpower Thunder Killer with his new form while the two hosts were having a brief conversation. While Thunder Killer launched an incredible lightning attack from his chest, Geed responded by using his cape as a means of defense. He then utilized Ultraman Taro's Ultra Capsule into his King Sword and defeated Thunder Killer once and for all with his Strium Flasher.


  • Suit Actor: Kazunori Yokoo
  • Paralleling Orb and Geed's similarity in their usage of past Ultras' powers, the similarities of Thunder Killer's components are as follows:
    • Both are Ultra Kaiju that was revived sometime later into another variant (Eleking was revived into Re-Eleking while Ace Killer was revived into Mebius Killer).
      • Additionally, some of their variants/upgraded forms have no aesthetic changes (eg; Re-Eleking, Eleking III, Mebius Killer, Victory Killer).
    • Prior to the conception of this fusion, Victory Killer (an upgraded variant of Ace Killer) is capable of turning its right arm into Eleking Tail due to using data on Ultraman Victory's UlTrans.
    • Both have alternate forms that never saw official on-screen appearances besides games and toylines, EX Eleking and Kabuto the Killer.
  • According to the creators, Thunder Killer's ability to redirect projectile attacks is the closest representation of Ace Killer's theft of the Ultra Brothers' powers.
  • Compared to most Belial Fusion Monsters, Thunder Killer appears to be a variant of Eleking whereas its name is a variant of Ace Killer.
  • Although using a regular Eleking as a component, Thunder Killer's "Eleking" color scheme matches that of the Discharge Dragon variant from Max.
  • In Ultra Kaiju Battle Breeders, his Timer Lightning attack is erroneously read as Killer Reverse.

Ultraman Z

Thunder Killer Z.png

A Celebro-possessed Shinya Kaburagi transformed into Thunder Killer, as well as Skull Gomora and Pedanium Zetton, after managing to forge the Belial Medal by using Riku's genetic data. Ultraman Z and Ultraman Geed faced the Belial Fusion Monsters, but were having difficulties due to Celebro's form changing. Suddenly, Ultraman Zero appeared, and the three of them managed to turn the tide on Celebro and defeated him with a combination of the Zestium Beam, Wide Zero Shot and Wrecking Phoenix. His Majesty's Medal


"Eleking! Ace Killer! This is the end mark."

―Kei's pre-transformation announcement

"Fusion Rise: Eleking! Ace Killer!"

―Activation announcement

"Ultraman Belial: Thunder Killer!"

―Transformation announcement

After scanning both capsules, Kei presses the trigger of the Riser and transforms into "Ultraman Belial". As the background changes into an eclipse, Kaiju Capsules of Eleking and Ace Killer appear briefly before "Belial" inhales them, morphing into and creating Thunder Killer.

"Eleking! Ace Killer! This marks the end for you!"

―Kei's pre-transformation announcement

"Fusion Rise: Thunder Killer!"

―Transformation announcement

Kei activates the Eleking and Ace Killer capsules, then loads them into the Riser as usual. However, Kei is not shown to transform into "Belial". Instead, Kei transforms in a burst of bright light after activating the Riser.

"Belial. Extradimensional Terrible-Being. Space Monster. Kiete karekareta."

―Shinya's pre-transformation announcement

"Belial! Ace Killer! Eleking!"

―Activation announcement

"Thunder Killer!"

―Transformation announcement

Shinya sets his Ultra Access Card into the Z Riser and then places three Kaiju Medals in the slots before sliding the blade and pressing on the trigger.



  • Height: 53 m
  • Weight: 52,000 t
  • Origin: Area S of Himuro
  • Arm Strength: 185,000 t
  • Grip Strength: 90,000 t
Powers and Weapons
  • Lightning Killer Cutter (ライトニングキラーカッター Raitoningu Kirā Kattā): Thunder Killer can launch red crescent-shaped (in Ultraman Fusion Fight!, it is blue or yellow instead), bolts of electric energy waves fired from its mouth.
  • Thunder Discharge (サンダーデスチャージ Sandā Desuchāji): Thunder Killer can charge its claw and tail with electricity to empower his attacks with 1 million volts of electricity.
    • Thunder Claw (サンダークロー Sandā Kurō): Thunder Killer charges its claw with electrical energy and slashes with it.
    • Thunder Tail (サンダーテール Sandā Tēru): Charging its tail with electricity, Thunder Killer uses it to batter opponents.
  • Talons: Inherited from Ace Killer, its left hand is also armed with talons over its fingers.
    • Deflection: The claws can be used to deflect attacks.
  • Killer Reverse (キラーリバース Kirā Ribāsu): Through Ace Killer's power, it can absorb and redirect beams. The energies first absorbed through the Color Timer, storing through its shoulder spikes before redirecting the attack via its mouth.
  • Timer Lightning: Thunder Killer can unleash a stream of lightning from the Color Timer on its chest.


Ultra Monster DX

Ultra Monster DX Thunder Killer.jpg

  • Thunder Killer (Ultra Monster DX, 2017)
    • Release Date: August 5, 2017
    • Price: 2700 yen
    • JAN/ISBN: 4549660167518
    • Materials: PVC


Ultraman Geed Kaiju
Ultraman Geed Alien Pegassa Pega | Skull Gomora | Alien Shadow (Zenna, Kuruto) | Alien Sturm Kei Fukuide | Dada | Darklops Zero | Alien Hook | Alien Pitt Tri-Tip | Eleking | Samekujira | Lunah | Arstron | Thunder Killer | Galactron | Tyrant | Alien Zobetai Nabia | Zandrias | Alien Groza | Alien Serpent | Alien Pedan | Alien Zelan | Alien Doble | Alien Neril | Alien Bado | Pedanium Zetton | Alien Ckalutch | Zegun | Cicada Woman | Alien Godola (Godo-Wynn) | Chimeraberus | Legionoid Dada Customize | Zaigorg | Mecha Gomora | Star Bem Gyeron | Lecuum | Gubila | King Galactron | Lidorias | Alien Reiblood | Reibatos | Alien Mefilas Sly | Alien Hipporit Jatar | Alien Temperor Villainous | Alien Groza Grocken | Alien Deathre Deathlogue
Ultraman Geed The Movie: Connect the Wishes! Alien Pegassa Pega | Jugglus Juggler | Galactron Army | Gillvalis | Valis Raider | Alien Jaki Arlon | MJ Galilee | Gukulushisa | Ruffle | Alien Norvar | Rawaan Man | Alien Gemaha | Idarada | Magdom | Bruck | Alien Nackle | Alien Ckalutch | Alien Shaplay | Galmess | Hupnath | Alien Bado | Kemur | Lecuum
Ultraman Festival 2017 Ultra Dark-Killer | King Galactron | Alien Pedan | Perfect King Joe
Ultraman Fusion Fight! Capsule Fusion MagaMaga-Arch Belial | Strong Gomorant | Bemzeed | Burning Bemstra
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Fight! Sevenger Sevenger | Jugglus Juggler | Crazygon | Diplas | Jirangon | Majaba | Red Smogy | Samekujira | Idatenran | Vortex Fire | SC-2 Prototype Machine | Gakuma | Ashuran
Sevenger Fight Sevenger | Jugglus Juggler | Jirahs | Alt-Helzzking | Eleking | Dancan | Pigmon | Garamon | Gazort | Reconstructed Pandon | Alien Icarus | Gandar | Alien Ghose | Beam Missile King | Pestar | Satan Beetle | Alien Boze | Alien Akumania | Alien Kettle | Oni-on