The Chouseishin (超星神 Chōseishin, translated as Ultra Star Gods or Super Star Gods) are the most powerful weapons of the ancient Earth Civilization. They remained dormant on Earth until the Gransazers were awakened, & reactivated the long-lost relics.
Each Tribe possesses one of the four Chouseishin, which can be summoned by setting all of their Knuckle-Risers to "Chouseishin Mode". One member of the Tribe can then "Dive In" & board the machine by setting their Knuckle-Riser to "Boarding Mode". Furthermore, by setting their Knuckle-Riser to "Sazer Gear Mode" the pilot can equip their Chouseishin with a large version of their personal weapon.
Each Chouseishin has two modes, which can be switched between with a simple transformation. In "Live Mode", they resemble animals & possess incredible maneuverability. In Warrior Mode, they resemble bipedal mecha, losing most of their speed but gaining immense attacking power.