I really like the characters and plot. At first I couldn't get into it because there was too much talking but after skipping those and going onward I became intriuged by the characters. One thing I like about this manga is that there's sex appeal. Male and female alike. And the characters are a bit cheezy but very likable.
But please, don't compare this manga to others. Like it for what it stand for and for itself.

First of all, the Mangaka is Masashi Kishimoto, Seishi Kishimoto's Brother (the mangaka for Naruto), so there is an obvious link between the two series. SO STOP COMMENTING ABOUT THEM BEING ALIKE. The two drawing these series grew up together, probably shared the same manga issues...

Anyways, I find the series decent, it doesn't have a superb anything, but good everything. It has little plot twists, small bumps in the story, good characters, but in the end it just lacks that spark that makes it stick with you. I find that it lacks that little bit that has me counting down the days to read the next release. I'd recommend reading this if you want a good read, but don't expect it to be that big read.

i realize the story arcs, art, and characters are similar to naruto, but taken at face value this is a great manga. the name through me a little at first, since i read the first volume under the american title "o-parts hunter" but i still enjoy it a lot. it's gat great character development, and just enough romance and scifi to keep it out of the people just beating on other people catagory. it's got a ton of intrigue and characters switch sides a lot. all in all it's a great manga.

I've only read a few volumes, around 6 or 7, I didn't mind the resemblance to naruto since both the artists are brothers, and they're different enough with their own styles honestly, I actually found it feeling more dbzish than naruto, but that's not what bothered me with the arts. The character designs and arts had similarities to also other series design-wise, dbz and bastard!! to name a few, not to mention some of the likeness to the story, and elements, it could be just me and being over sensitve.

I can't comment much on the plot however since I didn't get very far but it also progresses like typical shounen action manga which turns me off from the series.

Give it a try, but definately not my cup of tea and the first few volumes felt like a mess and felt unprofessional due to a few similaries to other series with amateurish art, instead of being "influenced by", it felt too close to being a Rip-off of a few great series you might know of, or it could be just my lame over analysing of a good series, but the overall flow of the story and everything together wasn't good enough to hook me.

great manga its just as good as naruto, no wonder since kishimoto seishi is the younger twin brother of the guy who makes naruto

It had a good story, though lots of things I could compare to Naruto, sadly (I never enjoyed Naruto) and because of all these similarities, it seemed less original. I could brush it off with the "same inspiration" excuse though. Now let's review...
I loved the story... to a point. I could do without a few things, but other than that it was fine. The way it was executed sometimes though, was badly done. Also, again, many similarities with Naruto.
Art was the same/close to Naruto's, but once again, "same inspiration" excuse was used for my enjoyment of this series to continue. I also don't think that Naruto and 666 Satan's is the best/greatest, many other works are ten times better.
Characters... some I liked, some I didn't. I disliked Ruby and Mei, same with other females that made me ashamed to be female. The characters weren't always chivalrous, and rash, which made me like the characters more (the stupid, brave, and strong characters annoy me after a time), but then again, some were like that.
I also want to point out, the ending wasn't as bad as people were saying... it just wasn't the usual "happy ending" that many prefer to have. Although it wasn't exactly the best way to end the series though... all in all, it was good, I enjoyed it.
This series deserves a 7.5, because even though it was a great story, it wasn't executed well, the characters weren't all original, and throughout the series, I always inadvertently compared it to Naruto.

i was interested at first because the main character looked like my oc when I was a kid...but the story is plain boring..i don't feel anything coming from this manga and the reason pushing the character are shallow..the art look like the one in naruto and part of the story as well (maybe because those two are brother) but i don't like naruto too bad..but I still prefer this one over n.

I liked the manga. I really did. And then the mangaka drew that crappy ending. That was a HUGE disappointment for me.

I'm going to be generous with my score, since I actually liked this better than Naruto at first. And at any rate, I still like this way better than Bleach. Haha.

666 Satan was the type of shounen manga that was associated with the like of Naruto/Bleach/One Piece, sadly it just fell short, in terms of plot, character development, and just looked like a major rip off, considering that he is the the twin brother of KISHIMOTO Masashi it didnt exactly bode well that they had a similar train of thought. The main character "Jio" was a practically Naruto, all that was missing was that he didnt say dattebayo every single minute. Sadly, this manga had great potential, had the writer just dared to be different and veered from that whole i will conquere my inner demon cliche. I think overall the mangaka did not execute what he wanted to do with his characters and therefore did not execute the way he wanted to tell the story. Up until the huge time leap, that came from no where, the story was pretty decent and just fell apart continuing to its demise as the ending ensued and a cr@p load of loose end were left unanswered. I give it a 7

For the majority of the story it's a fairly standard Shounen. Every character has their own set of gimmicks, secrets and hidden pasts that come up at just the right time to save their ass or advance the story and the story falls back on old standards like training and tournaments. The story starts to get more interesting and unique after the time jump but the time jump itself seems out of place. Right at the end several new characters are introduced and integrated into the main cast but before they're allow to develop the story is over. The the last 3-5 chapters probably contain about 25-50% of the whole story which makes me believe that the ending was rushed for one reason or another. There are also many similarities to Naruto but fortunately it's art style more than anything, the story and characters are far better. Overall it's a fairly standard Manga; if you choose to read it you won't be disappointed but if you don't you won't be missing out on anything major.