Seems he didn't fall alone, so perhaps Souboutei's evil is just the Moray that also went back in time, or at least that'd be a simple conclusion to make. But on the other hand, so far we haven't heard anything about why the Morays would be able to possess people through their anxieties, nor seen anything resembling them. They couldn't have built the mansion, either. In fact, the only thing so far that could possess people or twist their bodies or even care about humans and emotions, is the very "Grandpa" organism that saved the airplane passengers. And "where" is Makoto? Did he grow bitter after arriving alone (after God knows what kind of experiences he had in the time stream or whatever) and being unable to connect with people, since he's riddled with PTSD and has lived his life fighting a war on an alien planet? And looking at the colour of the two kinds of arms: the black arms aid Takoha, while the white arms take people away into the tunnel. Yet, the Morays were the ones living in black "water", while Grandpa lived in white water. The most similar thing to the Souboutei tentacles were Makoto's tentacles during the war with the Morays, too. And were the Morays even evil to begin with? A whole planet facing extinction, with a nearby source of nutrition that didn't even try to prevent their invasion, as it lacked any desire or instinct to survive, as well as negative reaction towards dying. Not particularly evil of them, though I suppose the following genocide may have embittered them just a bit. But were the Morays really the ones to bring the airplane there? If they could do that, why the tunnel, why not just jet themselves to Earth through space? So many question, and more that I don't have the patience to ask and you don't have the patience to read.