If I wasn't such a fan of this author's other works, I would have stopped my self-torture long ago and dropped this manga in its early chapters. Instead, I for some reason that's even beyond me keep reading along and getting the accompanying bad-plot headaches each time.
First of all, anyone that thinks this plot is any more a real fantasy story is along the lines of thinking that Twilight is the mother of all vampire novels. This "fantasy" story makes Harry Potter look sophisticated and creative. Basically, the story starts out on a quest but the characters quickly forget their quest as they get lost in the romance and butt-loving. Lots of copulation, professions of love, and life-and-death situations engineered to further the main pairing's relationship rather than further the actual plot.
The plot of this manga is definitely "reactionary" rather than "forward looking". Every few chapters, they meet some new enemy/challenged pulled out of nowhere that distracts rather than helps them in the original quest. The cities and the challenges don't connect to each other well either, and the arcs are very disorganized, disjointed, and confusing. I mean, Tsubasa: Reservoir Chronicle world hopping was less disjointed than the mere city hopping of this manga.
Other parts of this manga classify it into shallow romance BL manga format rather than fantasy BL manga with plot: 1) the introduction of too many pretty minor characters who don't contribute anything and don't have interesting personalities or backstories, 2) the serious lack of good females or females in general, 3) laughable battle scenes which take only a few pages to wrap up whereas each intimate scene is treated to much more screen time.
Don't come in here looking for plot because you'll just get eye-candy and smut. Her other work, Viewfinder had a more coherent plot than this (although Val is arguably a stronger character than damsel-in-distress Akihito). If you enjoy smut and PWP only, you'll have a great time reading this.
If you want BL manga that does actually have a plot with male/male romance as a bonus side dish, definitely check out Border or the very old school Tokyo Babylon. Or, some slashable fun ones: di(e)ce, Togainu no Chi, and (if your heart can handle it) the beautiful No. 6 (T_T)
I, for one, though really hope this manga concludes soon so the author will start up a better series.