Note: the following comes from a video review, links on my profile page.
Onikirimaru creates a world where the personal of what is (likely) to be humans watching is contrasted by that which, externally at least, is perceived to be not human, except if only actions are considered both the familiar and ogres run parallel.
A Shinto kind of aura pervades the anime, where a spiritual type of barrier is able to prevent the 'hideous' sort of nature that ogres emanate, shields that only function on such creatures... but what if reality isn't as binary?
These oni tempt humans to a point where their desires and even will can be overcome, where instinct is rendered useless by curses. The four episodes contain tales that can be seen as exploring extremes, whether love or hate (less of the former), friendship or friendlessness, even the very idea of non-existence when conflicted with the overwhelming force of the oni.
They are interesting, mostly stand-alone narratives; notice how the oni exploit emotions, this seems to be a feature of interaction with Japanese mythological creatures, like a kitsune who uses deceit.
Arguably the most pathos-filled of Kei Kusunoki's adaptations, it would have helped if characters didn't last just a single episode, but they are nonetheless stories with a start and end, which also could function as a commentary on a more in-depth thought than most anime with swords normally sustain. Most of the manga wasn't seemingly animated, though, what remains still complements Youma's atmosphere.
