User blog comment:Wrath022/Chapter 516: The Truth About Enchantment, Review/@comment-4507125-20161231163540/@comment-1776824-20170101083130

Dragons pass their magic on to humans through enchantment. Dragon particles don't exist. Antibodies is in reference to the seed, because the seed is like a virus. By sprouting, it spreads. It is almost quite literally a physical seed inside dragon slayer bodies. And as for the rest, B214 is right. And Gray's demon like abilities sprout from the already-confirmed fact that devil slaying magic corrupts your soul, and allows you to quite literally turn your body into a demon's, at least temporarily. The manga has been quite explicit with these facts by having characters explain them in literally terms.