My favorite Manga of ALL time. Absolutely. I've read a lot, but nothing surpasses this for me.
I just love the general concept of 'forbidden love'. In a sense that a dark or evil creature, horrific and shunned, somehow against odds is touched by a smaller and often more fragile soul. Nagabe's mind is brilliant how he portrays these 'forbidden love' stories in his other books too. I genuinly enjoy reading all of them. Even if the concept itself is used dosens of times, the way Nagabe approaches it is unique. For me, these stories surpass any of the other more popular Shonen. And yet again even if the concept itself is used before, I think its more powerful because of how misunderstood it is.
(Fun fact, it is what "The Ancient Magus Bride" was inspired from. So if you know that anime/read the manga, you'd probably enjoy reading these! The concept is the same, but the story is still very unique.)

Everytime a new volume is released, I sit on the edge of my chair on how the story unfolds, and it sometimes leaves me in tears.
So if you like a small heartwarming story that turns out into bigger, greater things, connection-wise, then I recommend giving this a go.
The art is different from a lot I've seen and it really fits the grim and obscure side. But then there's also the light and such comforting aspects. The balance between black and white elements are used so brilliantly to narrate the story.
And despite Nagabe is a more smaller author, I really hope he grows bigger to reach more people to tell his kind of love stories. I'm so happy and lucky to own them, which I also own the Vol. 8 Limited edition of Totsukuni no Shoujo, which includes artbook and Movie. The short movie is incredibly touching too. I suggest to watch that too if you like the manga!
I'm really curious where it will all go from here.

"I wish, I wish, I wish in vain, I wish I had my heart again,
And vainly think I'd not complain" - Siuil, a Run.
There's a reason why this great song is essence and always there around the books. So touching.