I loved this a lot. It's to the point where I wish I could jump forward in time two or three years to when more chapters have been released and I also know japanese enough to read it raw.
The title of this manga makes it seem weird, but for some reason they have a thing for ridiculously long titles, it doesn't mean much. The story is exactly as it says, a guy who was a knight was reincarnated into a super monster, a S ranked behemoth, and mistaken as an elemental cat and thus turned into a pet for the elf. This is out of his own free will, as she saved his life and helped him out etc, he wants to serve her... Well, I guess the boobs are part of it as well.
It's quite hilarious, there's A LOT of spirit and energy here and I never felt bored even for a second. Every character is vibrant. It's kinda funny how the elf is actually an "erofu"(instead of the normal version "erufu", elf), well, she's kind of someone with a bestiality fetish and a hardcore one at that, haha(don't bring crappy morals into this, it's fantasy with magic creatures that understand human language and a cat-like mc that is a human adult male on the inside, just enjoy it and laugh), the reasons for this isn't explained, but seeing her disgust towards males who drool over her and how she won't team up with a male at all, it seems to be hinting that something happened back in the day to cause her to turn out that way. Well, crossbreeding between elemental cats and other races are mentioned as something possible(he even got that skill from a groper monster at chapter 7), so perhaps we'll end up with half s-rank monster and half elf babies at the end? Wahahaha. His chances are good for some action, because after 8 chapters, he has already seduced the elf and a cat girl.
The cat mc can make a lot of nice expressions and his thoughts are greatly entertaining. I just love everything about it, the general feeling/mood and how it's written just clicks very well with me. It's all very nice, light-hearted, it's good fantasy and everything just flows well.
Seems it's written by one person and illustrated by someone else, I feel like they make a good team from what I've seen thus far. Usually it can be pretty hard for a writer and illustration to sync properly and produce a great result, especially since both would have to like what they're doing and we all know how much tastes differ.
Well, look at me praising it to the high heavens. Do remember that only 7 chapters were out when I wrote this, so after that I'm not really sure what happens, but as long as it keeps a similar story and mood, it will be all good. I wouldn't recommend a story for this to exceed more than 50 or so chapters though, 100 at most, otherwise it will probably get repetitive, boring and stale. But for now, I am just disappointed that there isn't more chapters. I wouldn't feel satisfied unless I read at least 20-40 more chapters... I even read the only raw I could find for chapter 8, at least what I could of it since I haven't learned more than a few dozen kanji yet.