@sssr
Thanks your explanation cleared up some questions, but then another question pop up again. If Nako died in the future due to a rule that soul can't manifest as solid matter in the earth and Nako hasn't been going to the planet just yet before senpai turned into portal why she's been...
There's some unfinished answer that I think about...
1. Who is the old alien that tries to give message to Megumi/Flare and Nako in chapter 21? Is it Nako's body that have been corrupted by Alien? Megumi that have been abandoned by Aimi? The Aunt? Aimi? or just an old alien?
2. What happens to...