Odin's plan looked pretty good: pretend to act in God's name to destroy the world, then use Thor's son as the savior and directly seize Earth's faith at its roots.
But...
The son Odin wanted could no longer be considered Thor's son.
Wait.
Something wasn't right.
Mephisto had his eyes on the essence Thor had left behind but had yet to digest. So, from a certain perspective, the son Odin thought was Thor's son was still Thor's son—but the inside of this son wasn't what Odin thought it was.
This child who was about to be born could no longer be considered merely Thor's son. He was also Mephisto's son.
Uh...
There was that worldview-shattering story that said twins could have two fathers. It could actually be applied here too, except this child possessed both Thor's bloodline and Mephisto's bloodline.
Jane Foster?
She was probably the first person in all of history to become pregnant with a son who possessed both the Thunder God's bloodline and the bloodline of Hell. This was probably beyond simply having one's ancestors' graves emit green smoke.
Her family's ancestral graves probably had to explode on the spot to grant her such good fortune.
"So what are you planning to do?"
"Put on a show. How can that old bastard Odin play both roles himself? There should be a protagonist on the side of justice and an antagonist on the other side. That's the way it ought to be."
"..."
Odin's original plan had been to both destroy the world and save it, just like his usual behavior and way of thinking. He wanted to be the great demon king who destroyed the world, while also being the great saint who saved it.
He didn't even understand such a simple principle as not being able