Chapter 69: Regarding alternative realities.
Every reality needs Aihana Etsu for the stability of the world from the side of science.Kanaru murdered Aihana Etsu in retaliation for teleporting him close to the sun to murder him, it didn't work. Aihana did that because no other person with his same ability could exist in this reality or the world could be destroyed. Ironically, he died and the world stabilized.
Then Kanaru met Rika. She came here because in this world there was no Aihana Etsu. When she saw that Kanaru had the same ability as Aihana, but not the same degree of power, she trained him for a few days (She does not have Aihana's ability, but she knows how to teleport between realities) and he quickly reached level 5. She it also informed him of the existence of other realities.
Then he met another Aihana Etsu, he was much more powerful than the previous one, but he only wanted information about this reality. So they both came to a cooperative relationship. Kanaru gives him information and Aihana does the same. By the way, Kanaru tried to kill him, but he couldn't catch him.
All this information I mentioned not so explicitly in previous chapters, but I think it is necessary to clarify so as not to get confused.
Realities shown so far:
Canonical Reality (Reality 1)
Dark Matter Project (Reality 2) -Here we are-
Aihana's World (Reality 3) -A world where Karui did not die and 2 years after Reality 2-
Rika's World (Reality 4) - ???? -
Weekly Power Status
-- Power
Ranking 
-- Power
stone