This is the problem: Fullmetal Alchemist dj - Book in Figure Red Comic. This was the first of three booklets (Named RED, BLUE and BLACK), each of which contained some side story to the series the author made to be released as an extra along with two small diorama Fullmetal Alchemist figures (and the mail-order exclusive BLACK version) designed by the mangaka. I don't believe this is a doujinshi as it was not self-published. Also, I think it might be better to combine the three as one series, perhaps just call it something like Book-in Figure series or Book in Figure Comics since separating them feels to me as though it would be a waste of pages.

Changed to Fullmetal Alchemist - Book in Figure

A just ruler amongst tyrants