Chika has a massive amount of Trion which explains why Neighbors are always after her. Trion soldiers collect humans with high amounts of Trion, and take the Trion glands of humans with low Trion ability. Then the Neighbors use the captured humans and Trion to fight wars in their world. It sort of reminds me of Fullmetal Alchemist.
I was definitely glad to get more of Osamu and Chika’s backstory. Chika’s older brother, Rinji, was Osamu’s tutor. Chika was being attacked by Neighbors long before anyone else knew about them, which makes me wonder how long they had actually had access to this world. Either way, only one person believed her at the time, but that person disappeared and may have been taken by a Neighbor, so she’s been afraid to ask others for help ever since.
Rinji said if anything ever happened to him, that Osamu should take care of Chika. I’m guessing Rinji was killed/captured by a Neighbor and that Osamu was there but couldn’t save him. But that has yet to be confirmed.
Before they can start thinking of ways to help Chika, the Miwa Squad arrives and tries to kill Kuga. We’ll see how that goes…