Inseiryuu
Inseiryuu, the Negative Pokemon, was once Arceus's equal. When Arceus was born, it was attached to Inseiryuu, who later unattached itself in a mad quest for power. However, as it tore away from Arceus, it nearly destroyed itself, and used the last of its power to create the "Lost Region" and encase itself as it lay dormant deep under the region's center. Arceus placed a shrine atop Inseiryuu, and posted two (immortal) guards to protect it from harm.
However, for an unknown reason, Inseiryuu had awakened, and massacred both the Dragon Shrine and its guards. It had still retained its mangled appearance, however this time, its body was harder than steel, and its soft belly had become encased in thick stone. With a shrill, bloodcurdling roar, it soared away in search of a host to take over, so as to restore its body and gain enough power to destroy Arceus.
Ability: Skinwalker - Allows Inseiryuu to change its appearance on a whim.
Times Type - Inseiryuu gains two more types during battle.
Species: Negative Pokemon
Type: Dark/Dragon (+Ghost/Poison or +Ghost/Steel, depending on the opponent)
Height: 10' 10"
Weight: 712 lbs.
