GrandGeneramon is the combined form of all of the 7 members of the Dark Generals in Digimon Fusion.
GrandGeneramon is an Unknown Level Digimon that resembles a giant monster with multiple body parts. His entire lower half is Splashmon's tiger mode. He has Olegmon's right arm, Apollomon's left arm and crest, NeoMyotismon forms the lower left arm and wings, as well as part of the body, Gravimon forms the lower right arm, his tentacles and part of GrandGeneramon's body, Zamielmon form the tail and part of the body, and Dorbickmon forms the head and chest.
GrandGeneramon has an incomplete version. In this form, both Olegmon's right arm and Apollomon's left arm and back armor are gone. Instead GrandGeneramon's arms are replaced with the lower arms of Gravimon's left arm, NeoMyotismon's right arm, and a third arm that takes the form of Zamielmon's arm.
After Fusion Fighters managed to defeat all seven members of the Dark Generals, AxeKnightmon arrived on the scene. He then performed a ritual to revive all of the seven members as mindless slaves. They all teamed-up and fought Fusion Fighters. AxeKnightmon eventually used his Darkness Loader and combined all seven Death Generals to formed the Ultimate Dark General; GrandGeneramon. As GrandGeneramon, he easily defeated both Shoutmon X7 and the members of Fusion Fighters with one blow. After the Fusion Fighters were easily defeated, AxeKnightmon trapped Shoutmon, Dorululumon, and Ballistamon’s souls in Prison Land.
Later, when Mikey, Shoutmon, Dorulumon, Ballistamon, and Olegmon, escaped from Prison Land and returned to the Digital World, with the help from Apollomon, AxeKnightmon Digi-fused the five remaining Dark Generals to form an incomplete version of GrandGeneramon. Despite it being weaker than it's previous form, GrandGeneramon still proved to be a powerful foe. Before dying, Olegmon gave the remaining strength he had to Shoutmon X7 it hopes it'll be enough to destroy GrandGeneramon. With the extra power, Shoutmon X7 managed to destroy GrandGeneramon for good. Upon GrandGeneramon’s demise, the five remaining Dark Generals disintegrated into nothingness.