I just finished the manga for this myself, got bored, and decided to make a thing. I'll split up each arc as they are listed on the wiki, while combining some of the smaller ones to save a bit of time and space. I'll go first, and anyone else is free to chime in with their ranking. I'm sure I'll be preaching to the choir here, but that's okay, it's a hobby of mine :) It's also important to remember, that while I'll be criticizing a lot of the story, I really liked it overall. This is one of my favorite series.
The first three of these are really close, and are basically interchangable, here we go:
1: Seven Walls Arc (Ch. 131-145)
I think this just slightly beats out everything else for me. I know a lot of people don't think as highly of this one as I do, but I'll try my best to justify it.
Perhaps its just because this came directly after a couple mid arcs, but I LOVED this arc. Personally, I think this is the only arc in the second half of the manga that can stand up to Goldy Pond and Jailbreak. It follows 3 different engaging storylines at once: Emma and Ray stuck looking for him in the maze he created, Don and Gilda looking for Sonju and Mujika (and trying to covertly keep them safe in the process), and Norman preparing to raid the imperial capital. It manages to switch flawlessly between each one, and give ample time to them. I love it when a piece of fiction splits itself like this, and is still able to make each one suspenseful and interesting.
Demisu Sensei's art, while already amazing through the entire manga, went to another level in this arc. It's honestly some of my favorite art in manga, period. This sequence where Emma and Ray were turning back time had my jaw on the floor:
I definitely think this arc is underrated amongst fans and deserves more love.
2: Goldy Pond Battle Arc (Ch. 75-95)
I probably don't need to say much about this one, as (I think) most of the fans love it. I was on the edge of my seat basically the entire battle. I absolutely love, love, LOVE the design of all the Goldy Pond demons. Specifically Nous, Nouma, and of course, Leuvis. The one problem I had with this arc, and probably the only reason it isn't at the top...
You mean to tell me all of those kids made it out alive? Really? Sure, a couple were lost in Goldy Pond, but thats technically not in this arc. This continues throughout the series, so it's not just confined to this arc, but it's a minor thing, this arc is still one of the best in the series. The action makes up for it.
3: Introduction/Jailbreak Arc (Ch. 1-37)
Not much to be said. The absolute classic that started it all. I would imagine most fans would likely put this one at the top, and it definitely deserves it. The introductions, the plotting and scheming, the mystery, the suspense, it's all amazing. The night of the escape itself is probably my overall favorite sequence in this manga.
If I'm bored, I always find myself just rewatching season 1 of the anime, which is just this arc, and I'm sure I'll be re-reading this too when I have nothing else to read.
The next two I would rank considerably lower than the first three, but pretty close between each other:
4: Search For Minerva Arc (Ch. 53-74)
While this one started off with a bang (or almost, right? Get it?... Yugo put a gun to Emma's- you know what forget it, dumb joke XD. Small tangent, but can you imagine her dying there? What a different story we would've had.), but felt a little slow. Slow, that is, until they start the trip to Goldy Pond and Emma gets kidnapped.
Violet, Oliver, Nigel, and Gillian all became some of my favorite characters, and they were all introduced here.
5: King of Paradise Arc (Ch. 113-130)
NORMAN WITH THE ABSOLUTE GLOW-UP.
But for real, the reunion was definitely touching, and made me happy cry for them all. In my opinion, I really don't like the direction that Norman went after he reappeared, but that's just a personal thing as I think he's still a decently enough written character. We got two completely different plans with how to move forward from Emma and Norman. While I wasn't fully on board with either, the fact that they chose to both go forward gave us the beauty that was the Seven Walls arc, so it gets an extra point for that.
Not the best arc, but far from the worst.
The next two are also pretty close amongst themselves, and I'm divided on exactly how much I like them:
6: The Promised Forest Arc (Ch. 38-52)
Mujika and Sonju are two of my favorite characters, so it pains me to have this one this far down the list. This arc basically serves as a lore dump and training arc, but still manages to be good. I personally think it's the weakest arc in the first half, but still better than a lot of the second half.
7: Return to Grace Field/Human World Arc (Ch. 160-181)
So, oh boy. The ending. I know people hate on this ending (and the last half of the manga in general), but I thought it at least tied things up neatly, if a little cheesy and cliche. That's shounen for you, eh? Peter Ratri's story came to a bit of an unsatisfying end, but it was made up for by Isabella's heroics and redemption, imo. The reunion with Phil was also very touching.
In general, I was inconsolable and bawling the entire last handful of chapters. My babies all made it. They're alive. But oh god, how could you do this to my baby Emma :( Sacrificing herself would've sucked, but I would've understood it. It's in her character (this is too admittedly. She'd give up anything to save her family). I just didn't expect something this... cruel... from this manga. I'm sure they'll tell her all about their time together, but thinking about how she doesn't remember their journey just hurts my heart.
An important distinction to make is that I don't dislike the ending itself, but this arc did feel really underwhelming in places.
Down to the final two! First up, an arc that is this low, because it could've been so much better:
8: Cuvitidala Arc (Ch. 96-112)
My problem with this arc isn't what it did, but what it didn't do.
Let me start by talking about what this arc did really well: Made me bawl like a baby. Seeing Yugo and Lucas' story come to an end was easily the saddest part of the manga for me. The raid on the shelter definitely had me on the edge of my seat, but wasn't quite on the same level as Goldy Pond for sure.
On the other hand: That raid on the shelter felt completely disconnected from the rest of the arc. The actual Cuvitidala part of the arc took what, 3, 4 chapters? I think the biggest missed opportunity in this manga has to be not expanding on them exploring for the temple and having to disguise themselves in the demon towns. That was such a cool premise and I was so disappointed to not see it expanded upon. (We do of course see that in the imperial capital, but not in a way that presents any danger or suspense)
And speaking of the imperial capital...
In my opinion, the worst arc in this manga:
9: Imperial Capital Battle Arc (Ch. 146-159)
This was the closest I came to not liking an arc in this manga.
While the art of this one definitely retained the bump from the Seven Walls arc, it was a little hard to follow in places during the battle between the Geelan clan and the regent houses/Queen Legravalima. Norman, and the queen to some extent, both succumbed to Talk no Justu from Emma, and a lot of things in this arc just felt like they kinda... Happened. The last few chapters were pretty good however.
Who knows, when I enevitably re-read this series, I may think differently of it, but I doubt it. This was easily the worst one for me, but even so, I still enjoyed it about as much as I disliked it.
And there's my list that no one asked for XD I'd love to hear what everyone else thinks as well! As I mentioned, I just finished the manga, and I'm very sad to see it go. I know a lot of people have a lot of problems with the manga, and while it certainly is flawed, I can't remember a piece of fiction burning itself into my brain like this one.