Ghidorah can never truly die, and if his body isn’t around, his spirit is. The 3 heads, Ichi, the short tempered and responsible middle head, Ni, the aggressive and restless right head built up on rage, and San, the calm head that is slowly turning insane and aggressive from his soul going into Mechagodzilla only to be killed again. They have much knowledge, and are trapped in somewhere beyond the 3rd dimensional world and can defy any law of gravity in their world.