Unlikely but possible relation between Mothra 3 and Legendary Ghidorah

2 Ghidorahs(1 headed) await their egg to hatch, as it hatches they notice it has three heads (which has never happened). They notice it is also extremely aggressive, so they hide it in a cave and seal it. As it gets older, it breaks out, with an intention of wiping out life including other 1 headed Ghidorahs, he instead encounters several monsters refusing to let the home get destroyed so easily, monsters such as Mothra, Rodan, Titansaurus, certain stronger Zillas (Zilla Jr reference) and finally Godzillas. He kills many of each species until he encounters the last defender Godzilla. King Ghidorah realises the size, strength and experience of this Godzilla and decides to do a stealthy approach, while Godzilla is out, leaving his mate and child (Minilla, Godzilla Jr reference), King Ghidorah then attacks Godzillas mate and child, Godzillas mate tells baby to run away while she holds Ghidorah off, since females have twice as much nuclear reserves, she uses all her reserves in a powerful Spiral Ray which does a little damage to Ghidorah, which is quickly regenerated, he then takes his time killing her. He goes in search of the child, who goes into the sea swimming as far away as possible to never come back, he goes straight to an ice biome, where he is frozen but still alive. Godzilla returns to find his dead mate and no sign of Ghidorah, also thinking Ghidorah killed his child, a grudge forms between the 2, Ghidorah and Godzilla have a short battle from which a few Baragons help Godzilla by burying Ghidorah deep close to the mantle of Earth. Godzilla still holds this grudge, causing a ferocious battle in the current day. Rodan's offspring were also killed by Ghidorah and Mothra's parents were killed causing them to also hold grudges. At the end of the movie, Godzilla finds Minilla/Godzilla Jr is still alive.

I also like how design 1 uses King Ghidorahs wings, I hope that can be implemented in this design