Tsuagon is a Giant Dinosaur that first appeared in Tsuagon The Subterranean Terror.
Tsuagon has light tan skin, a coffee brown underside, a yellow horn, white teeth, white eyes, gray finger and toe nails, and a pincher at the end of his tail.
Tsuagon's personality type is unknown, but it is known that he does not like to fight other kaiju, but only if he has to.
Tsuagon can produce a beam of sharp, blue fire-like energy that can cut through things with ease, that includes tough hide like Godzilla's. He can transform between his normal form, and NEO Tsuagon, but only if he has the energy to do it. He can also grab kaiju by the end of his tail and swing them around with ease while injecting poison into the kaiju.
Tsuagon is a result of a failed experiment by Dr. Serizawa, code named TSU. He got some old dinosaur cells (from Baragon) and some unknown cells (From Gyaos) and spliced them with cactus cells (for spikes) and he wanted the end result to be something to kill Godzilla, but instead since he didn't know what cells he spliced, the end result was a kaiju he dubbed Tsuagon. Tsuagon did fight Godzilla, but was defeated, and right before he died, he laid a egg and another Tsuagon came out to defend Humanity.
- Tsuagon's name is made of up of the words Tsu and agon. Tsu means "Bay" (from the word Tsunami) and agon is from the word Dragon.
- Tsuagon had multiple designs up until the Gyaos design was choosen, the official name of Tsuagon's design is called ShodaiTsua.
- Tsuagon was going to changed to "Ashuagon" but was scrapped due to the similar of creator's name.
- Tsuagon was inspired by Baragon from Frankenstein v.s Baragon, with his horn, and his roar has a bit of Baragon in it.
- And finally, the creator tried to replace Tsuagon, but was too happy with the result of his kaiju.
- Tsuagon has the design of "South Korea's Godzilla," Yongary. Except he has light tan skin and his abilities are different, he is NOTHING like Yongary in personality and abilities, but in design, they look the same.