I dropped this manga two years ago while waiting for it to be completed only to realize that it's already completed since last year lol. I wasn't really expecting this to end with them graduating. I always thought that there would be some timeskip where they become adults. But it refreshing to finally get some closure with this one along with Caste Haven(▰˘◡˘▰)
Every time I'm in the mood for some dark themes, harada's work is my go to. For this one, whether you liked it or not, one has to admit that it really is well written. Specially the psychological aspect of it (which is what I love about all of harada's work that I've read). I've read other artists/authors who try to experiment with psychological BLs before and it is either too unrealistic or exaggerated even or its lacking in some way but Harada manage to find the balance wih their work(a comment below explained this better).
I've read a lot of manga/hwa/hua with similar premise of confinement and mind break like this one but personally speaking, nothing beats Harada sensei's mangas with these type of stories. It's not about how dark the story is, but the process on how the aggresor slowly breaks into the victim's mind, this is what I find lacking in most stories, just like this one.
Here's one that has similar premise as this story (kidnapping&confinement): Gintama dj - Mienai Kusari
If you are fine with reading fanfics you can go ahead with this one. It is also a short story but the delivery of the plot is really good. Just be aware that it can get more disturbing, disgusting even, as compared to "Tosa's Master".
As much as I hate the ML this chapter did not make me happy like the others here is com sec. As someone who play sports, cheating and tampering on your opponents belonging to gain an upper hand is something that irks me to no end (╬ ̄皿 ̄)