Using the memories of a demon and the story unfolding from multiple perspectives, it tells historical stories and resolves various misunderstandings.
"Hey Seral, what are you thinking about?"
"I wonder what the future world will be like."
"Hey - it's really strange. Why don't we make a promise and see the future world together?"
"I think it's okay, and I can still witness the friendship between us."
"Then it's settled"
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"... Didn't we agree to go see the future world together?"
"Seral... For this world"
"We... Must do this"
"So how about you live on... Look at the future for us?"
"You are just a bunch of liars"
"Seral we're sorry, so please"
"... Good"
Concept: Various Western elements