The Jyamatos are plant-like monsters who devour worlds through their evolution. They serve as the main enemies of the Union Grand Prix.
The Jyamato have existed for many years, but are not known to the general public due to the UGP erasing the memories of them from all those unaffiliated with the organization. The Jyamato are created and grown inside the Jyamar Garden from tree-like plants, who feeds on the bodies of deceased Union student/professor or villains, which causes them to evolve much more rapidly than other forms of life.
Their overarching societal structure and motivations for attacking humans are currently unknown, but their basic behavior and physiology seems to change with each incursion into civilization, centering on a specific schema that the UGP uses to organize different games.
There are currently five known categories of Jyamato; Pawns are the weakest and function as foot soldiers. Rooks are much stronger than pawns and are capable of defeating armed Riders on their own. Bishops are currently seen to take on human appearances as a disguise, Knights are among the strongest class of Jyamato, and according to information from the UGP, can potentially become powerful enough to destroy the entire world, while the non-humanoid Fortresses are naturally giant than normal-sized Jyamato, and often appear in the final round.
While their intellectual capacity is unknown, they are able to speak their own language. Their evolution from being fed upon the deceased Union members and villains seems to be much more drastic in terms of their offensive capabilities.
Known Jyamatos
Pawn Jyamatos - Weeds (not the drug kind)
Rook Jyamato - Pitcher plant
Bishop Jyamato - Mushrooms/Fungus
Knight Jyamato - Cactus
Fortress Jyamatos - Slugs, Rafflesia
Jyamato Rider
The Jyamato Riders are Pawn Jyamatos who evolved enough to gain the power and intelligence to transform using the Desire Drivers and the Jyamato Buckles. Their evolution is the result from devouring the corpses of Union members and villains.
Jyamato Riders are significantly stronger than the usual UGP Riders or any higher ranking Jyamatos including Rook, Bishop, and Knight, beating several of them with a single punch. However, they are capable of being defeated with enough force, such as utilizing an upgraded Raise Buckle. They can be defeated in normal Raise Buckle Forms or even in Entry Forms, though a rather brute force is required to do so.
While the creation behind the Jyamato Buckle is unknown, it is presumed that it was created from the regular Raise Buckles that were combined with the essence of a Jyamato.
Normally the Jyamato Buckle are mainly used by the Jyamatos themselves, they can also be used by humans. However, the transformation process is quite painful and can result in the user slowly transforming into a Jyamato.
The Jyamato Riders can also use other Riase Buckles to power themselves up.
Personality:
A Jyamato Rider is capable of some level of human speech, as they can utter "Transform/Henshin" upon activation of their Desire Drivers. They also are relentless in the pursuit of their targets, continually attempting to destroy them. It also seems that whenever a Pawn Jyamato obtains a Desire Driver and a Jyamato Buckle, they will gain intelligence and resume the pursuit of their fallen comrades.
While they normally attack the Riders out of animosity or some sort of hostility due to being their enemies, they see the Union members and villains as food.
Due to being born from the corpses of their victims, the Jyamato Riders, outside of their Rider Forms, can imitate their appearances and personalities.
Age: Unknown
Gender: Varies
Aliases: Monster Riders
Rider Type: Villain, Troops
Affiliation: Themselves
Likes: Devouring/Killing humans, Evolving
Hates: Kamen Riders, Union Academy, villains
Motif: Plants, Thorns, Vines
Theme Song: Odds n' Ends by Jyamar Garden
Form
Jyamato Rider
Equipments
Desire Driver
Jyamato Buckle
DisCore ID