TLDR here: A plot-driven, ecchi, trash manga with an initially fun premise in a battle of wits to make other people their slaves with a special mouthguard called an SCM that falls deeper into the trenches at the end. Grievances: (Some Spoilers) Characters: The manga had two "main leads" Eika and Yuuta at the beginning of the story, but kind of fall off by the end. 23 characters are introduced in this battle of wits some more off handedly than others. The author seemed to have had a good time creating a range of different characters. The cast of characters the audienceis not provided much insight into a majority of them or mentioned offhandedly in a few panels. There was not enough time to care what was happening to the characters. Character relationships made no sense, they really only acknowledged each other that often until they have a part to play in the story or give a tiny bit of context.

Story: Maybe the manga got axed or something with how short it ended up being. The initial idea of manga is very gimmicky but could have been at least a decent read. It got darker as it went along which is also fine. The quality takes a nose-dive 2/3rd into the story around volume 6. The ending was much to be desired with the two initial characters we are introduced to having little impact at the last showdown. As another reviewer noted the last tactic was that a ghost helped win the ending...

What I personally hated the most: Mostly nitpicking.
There's a limit to how story-driven something can be.... The logic of the characters and/or character motivation gets really blurry at the end. There is a character called Julia (unknown age probably an adult? At the very least 17.) who has a somewhat ambiguous relationship with a literal child. It is unclear at the end if she just discovered she loved being a slave to him, seen as a mother figure or a something a bit more dubious. It is never clarified truly why she feels the way she does either. Nothing directly explicit was shown, but if that makes you uncomfortable then this definitely is not the manga for you.

The epilogue was seriously unsatisfying, it didn't give much closure other than they were all free. There's one character's ending in particular that doesn't make sense. The host (who is Julia's ex-boyfriend) ends up with the girl who forced him to be her slave/boyfriend. It is not explained or alluded to that he made up with the girl. Julia and the host do not acknowledge each other properly like you would think they would given her circumstance in the ending.