Oni Gari is a strange read.
Now, I know what you might be thinking, this is a horror manga (labelled as hentai here on MAL) by the mangaka who also set the world's obsession with tentacle porn in motion. Strange, with him, is to be expected, and, more than that, should be celebrated too.
But there's not that much to celebrate about Oni Gari.
Ultimately, Oni Gari is best described as a disappointment. The first scene is sexual, which one would presume is a good indicator as to what the rest of the volume will contain; this combined with the introduction of the ogre seems to be a
clear indicator of some kind of beastiality/noncon/perverted shit to follow, the type of stuff that the rest of Maeda's works include. Why would you presume otherwise? And yet, if you did presume that, you're mistaken. Oni Gari is really not a hentai, and most definitely not a ero-guro work either. There's hints of rape, but nothing's shown, and, though one of the monster's cries out "I'll rape you and then I'll kill you" towards the MC, that never goes anywhere either. Oni Gari is just what it says on the tin - there's an ogre hunter hunting an ogre cause said ogre is hunting a girl.
Now, ero guro (nor sexual scenes in general) is not what makes a good manga, and, in theory, Oni Gari could have survived on its plot alone. But the plot's boring, uninteresting, and very simplistic. It's like the mangaka went, "huh, now why would a ogre hunt a girl? Cause he's been told to? Yeah, sounds good, we can check that plot hole off the list." Arguably, if that's what your plot's going to be, you might as well just go for porn without plot. But, of course, Oni Gari doesn't have much porn to begin with; it's just got a dude yelling chants to save some girl (notice the use of 'girl': I finished this manga five minutes ago, and I've already forgotten everything about the MC. She's that forgettable) and a hella ripped ogre.
Anyway, overall, 4/10, don't expect to jerk off to this, don't expect to enjoy it either (unless you're a Maeda fanboy, but even then, I doubt you'll love it). The redeeming factor is that the art's alright - emphasis on "alright" and not good. All Oni Gari is is clickbait from the 80s. You start off with the sex you were expecting for Mr. Tentacle himself, and you finish up with absolutely nothing.