Origin

Todd Ziller is a corporal in the United States army. When he was in college, he was in a philosophy class when his atheist professor dared God to smite him within 15 minutes. Just as the time limit ran out, Todd stood up and punched his professor in the face. This sense of character is what got the attention of Gen. Robert L. Maverick. Maverick was in charge of Project: Troubleshooter, an attempt at recreating Dr. Erskine’s super soldier serum. The scientists involved used a number of transformative sciences including, gamma radiation, mutant growth hormone, pym particles, and Dr. Connors’ lizard serum.

This transformed Todd into a reptilian kaiju.

Creation

American Kaiju is first seen in a premonition of the future in Avengers (2015) one shot. His name is a pun of Godzilla, the most popular kaiju in fiction.

Major Story Arcs

Avengers Idea Mechanics

After Sunspot took over A.I.M., he re-branded it as an Avengers operation but received a lot of bad attention from the U.S. government for “hiding in international waters.” The last straw was when he sent his field team into a SHIELD holding facility to retrieve Rick Jones, who was apprehended for his crimes as the hacker, Whisperer. In a closed room meeting about what to do about Sunspot’s new organization, Maverick suggested they activate the American Kaiju.

As soon as the Kaiju wades ashore on AIM Island, Sunspot has his biggest guns get into his giant 5-pilot mech to fight the giant one on one. The mech proves to be no match for the Kaiju, which fights with US military training. So, Sunspot throws a hail mary play by venting the gamma core. The sudden burst of gamma energy triggers Todd’s transformation trigger, turning him back into a regular human. His body was never recovered.

Rabid in Europe

Ziller would go to mad scientists looking for help to return to his beastly form. He had become obsessed with it, practically addicted to it. A scientist by the name of Victor Van Doom, jealous of Victor Von Doom’s success, was able to extract Ziller’s blood and re-create the serum. Because Ziller’s monster form is far from inconspicuous, it was immediately leaked to the media that an American flag-clad monster was running rabid through Latveria and Symkaria, threatening an international political dilemma.

Since his previous fight against Avengers Idea Mechanics, Sunspot had made a deal with the U.S. government and re-branded his organization yet again to American Idea Mechanics, a division of SHIELD that deals with large scale mad science. Among their ranks was Ziller’s former commanding officer, Gen. Maverick. He had been outfitted with a special plug-in that would allow him to be a Red Hulk for an hour. He was considered the best person to go in and confront Ziller. Freshly dosed by Van Doom, Ziller tried to fight Maverick but was bested. The Kaiju was thrown into a nearby castle, destroying it. This incident made the papers, much to the chagrin of Captain America and SHIELD.

King in Black

Ziller was back in U.S. custody when Knull, the King in Black, invaded Earth with his army of symbiotes. Part of the army were flying symbiote dragons that American Kaiju was released to take out. During the fight, Ziller reflected on the path he volunteered for. He agreed that the symbiote dragons were a clear and present threat and understood they needed to use their biggest threat against them. However, he saw how he destroyed everything he touched and doubted if his actions were really warranted. Regardless, he fell in line like a well trained soldier despite his misgivings.

Protocol: Omega

Ziller was partnered up with John Walker aka U.S. Agent for a number of official American operations. Their newest mission was to attack Latveria, however, it was an operation manipulated by the Red Skull to give him cover to make an escape from his Latverian bunker. Bucky got intel on this manipulation and tried to stop them while they were waiting for their greenlight in Hong Kong.

Unfortunately, Red Skull had already planted a mind control program, Protocol: Omega, on Ziller, forcing him to change into his beastly form and attack Hong Kong. With a mystical artifact given to him by Shang-Chi, Bucky was able to increase his size and fight Ziller one on one.

Walker, who Shang-Chi was trying to distract, eventually got Bucky's attention and convinced him not to kill Ziller. Instead, he knocked Ziller out and managed to change him back into his human form. He was then taken into custody by the US, while Walker agrees to join Bucky's Thunderbolts against the Red Skull.

Powers and Abilities

Military Veteran: Ziller is a trained soldier in the U.S. army reaching the rank of corporal.

Super Soldier Serum: Ziller was subjected to a version of the Erskine's super soldier serum, with a number of modifications trying to fill the gaps that Erskine took to his grave. These specifically worked to turn him into a Kaiju.

• Gamma Radiation: Gamma radiation was used as a mutation trigger
• Pym Particles: Pym particles were used to increase his size
• Lizard Serum: Dr. Connor's lizard serum gave him reptilian characteristics including claws, fangs, and scaly skin.
• Mutant Growth Hormone: The synthetic drug, MGH, increased the efficiency of the other transformative sciences.