The idea of each knight having to act a certain way is quite original, many other characters of different series gain powers in a similar manner, but its flawlessly executed in this series. Even the interactions between the knights are part of their personas.
The story follows their leader, who has the most restrictions and is rather frustrated by them, just as his predecessors. And the power they gain is quite underwhelming compared to their own abilities and it's given by a god whose existence is questioned by the very knights that represent him.
The story isn't perfect. Since it's a Shoujo, don't expect an extremely complex story. From the beginning you'll probably expect who the death knight is (they constantly hint it). But It's still a good read since to has to resolve everything staying in his persona.
The comedy is a strong point, and lots of things are inserted to ease the tension created by the rather grim plot of the first part (you could probably skip the MC taking care of his appearance and give less focus to the characters with a sweet tooth when they're eating). Though if they really did that or focused on other mature aspects they DO mention ... it probably wouldn't be a Shoujo.
All in all, I'm definitely not part of their target public, but given it's on old manwa I'm quite impressed, the story might seem to go slow for all the added parts, but considering the length of each chapter and how they're advancing towards the conclusion of the ark every moment, it leaves new manwas in the dust (I abhor most new manwas because they usually only contain what I considered the added parts, are short and go nowhere plotwise).