Oh, you ask for the name of this pit? Regarding the "1" in the name of this pit "1+1=1", please understand it as a world, not soul fusion or the like.
Oh, you ask about the writing style? This article is a writing practice, and the plot should be as serious as possible + floating clouds [What?
Oh, you ask the protagonist? The protagonist's name is confusing, and the world is a fusion of two worlds. Please don't get too hung up on the settings. After all, this is a writing practice.
Oh, you ask CP? I am personally a fraternity party.