Having watched up to Episode 11 of
Toilet-bound Hanako-kun.
As Nene meets Mitsuba for the first time, they are stuck being attacked by School Mystery #3. Though with Hanako unable to answer Nene's calls, instead we have Tsukasa answering Mitsuba's cry for help. Though what happens next is something most notable. Tsukasa one-shots School Mystery #3 even though his Yorishiro is still active. This really adds speculation in terms of who is Tsukasa because we know against Yako Hanako was struggling against her until her Yorishiro got removed.
It really speculates that Tsukasa is even more dangerous than we originally expected.
One big information tidbit learned from this episode is what are the uses of the boundaries for each of the school mysteries. As Tsuchigomori's boundary serves as school records as we saw during his arc. Yako's is space and that space can venture into other school boundaries. It is curious to learn more what are the uses of the others as the story progresses.
Hanako and Kou arrive quite late to the scene where they see Nene unconscious and Mitsuba looks different. This is because he basically ate the 3rd School Mystery and has taken over that role. Though there is a conflict between him and Hanako as Mitsuba wants to be human, which is his wish and regrets. Of course, we know that this Mitsuba is not the same one that Kou met a few episodes ago. As Tsukasa called it, it feels like an artificial ghost. The outside looks like Mitsuba and his personality remains intake. But memories and experiences are gone.
As we saw Tsukasa deal with #3 effortlessly, Hanako has his trouble against him. Which really raises the question of why is Tsukasa so strong? Though one really nice scene is Mitsuba saving Nene. In many ways, that showed the humanity of Mitsuba still lives inside as the time these two bonded borne fruit here. Though where Kou goes from here is interesting. Does he try to save his friend, or will he give up?
Also, what is Tsukasa's plan in general besides unleashing chaos. He has collected a school mystery on his side, but there is so much uncertainty between him, Sakura and their group.