Warrior of Fire Skill: Fire Breath (Attacks the opponent by breathing a massive flame from the mouth.) Extremely loyal to his master, Rex. (The image on the right shows Ultra D-Buster Tyranno.)

Warrior of Lightning Skills: Lightning Beam (Emits electricity from the mouth), Electric Drive (Increases speed to lightning levels) Only trusts his master Rex about 80%. (The image on the right shows Ultra D-Buster Saber.)

Warrior of Earth Skills: Stone Break Barrier (Summons a shield to block opponent's skills), Ground Hole (Binds the opponent to the ground) He is a bit silly and laughs a lot. (The image on the right shows Ultra D-Buster Stego.)

Master of the Ultra D-Buster Transforms using the Tuner equipped on his arm. (The image on the right shows Rex in his transformed state.)

Rex's friend who currently has a crush on him. She dislikes John intensely and only hangs out with him because they are mutual friends.

Provides information on Mecha Dinos using the Dino Book.

Serves as the legs of the Ultra D-Buster.

Serves as the wrists and hands of the Ultra D-Buster.

Dark Angel Kaya, a subordinate of Darkno. The image on the right is a disguise used to deceive Rex and his friends.