So many people elsewhere have lamented the short length and I have to join the chorus.
There's already such a rich framework here, full of colorful and intriguing characters, thorny dynamics and painful past that doesn't get fully explored in a single volume. I've heard that there is a sequel to this now, and it's such a welcomed move, but even so I feel like this specific story could have been made into 2 tankoubons and I wouldn't complain at all. It's that good.
But even as it is, everything that we see here is very good and delicious. Now the premise may be pretty standard, but the execution and the details more than makes up for it. While the story doesn't really delve deep into the supporting cast, the pacing of the main story is well-made. The relationship between our two main characters unfold really nicely despite the rocky (dubcon?) start. So is Zein's growth. The action scenes may be sparse, but it flows well and feels dynamic enough to be alive. And the smut, when it does happen, is hot and lewd and intimate.
A special mention must be made for Raihan Rille/Lil. He's easily the beating heart of the story, chaotic and debauched yet generous and compassionate. And he's really, really hot. Yay switching.
It's really a story that leaves you wanting for more.