On the other hand, Berserk's strange obsession with out-of-place lightheartedness and "joke characters" changes the dynamic of its darker aspects. Out of the current protagonist lineup, half of the characters are, in essence, jokes - two pun-cracking, reference-making faeries and two children who inexplicably survive all the things that kill grown adults. When I say "jokes", I mean "jokes" - like, "Genie from Aladdin"-level "jokes", just taking things from pop culture and slamming them halfheartedly into the narrative. It's hard to get a sense of how serious the manga is meant to be because it keeps changing its stance. But let's start by looking at its good aspects.
Berserk takes place in a world largely akin to our own circa the 16th Century; like Warhammer Fantasy, each nation in the Berserk world is essentially meant to take the role of a real-world nation ("Midland", the primary nation in the series, was stated in an interview to be Denmark, while its enemy "Chuder" is designed around France). Berserk's world, in normal circumstances, is one of standard period intrigue - wars between nations, succession crises, arranged marriages, and so on. The technology and designs of the world seem to be largely conventional - plate armor, melee weapons, crossbows, and so on.
Berserk's "fantasy" element initially comes from the demonic Apostles, monstrous beings who are "created" when a human with powerful ambitions uses an artifact called a "Behelit" to abandon their humanity in exchange for greater power. The Behelit are the tools of another world, and the Apostles bend to the will of that world's rulers. Apostles are far stronger than normal humans, and many of them can destroy armies with ease; their rarity is what keeps them from wiping out the entire world. The Apostles provide the only real "unrealistic" element for much of the series, appearing even in the very first chapter. Later it is revealed that magic exists "normally" in the world, though it has been largely forgotten except by certain individuals. As the series progresses, the fabric of reality between the Apostle's world and the "normal" world weaken, leading to monsters like trolls, ogres, goblins and dragons appearing around the world.
Berserk's setup allows for a fairly grounded and justifiable "fantasy" setting. While most fantasy settings seem to be intrinsically at odds with themselves (i.e. "why is there medieval stuff when magic exists"), the fantasy elements in Berserk are outside the realm of normal human activity. The monsters in the series come from another plane of existence and are reasonably rare to boot, while "magic" in the Berserk world is practiced by a very small number of people. As such, Berserk is a setting with both monsters and magic, but it also explains why normal people behave realistically and have realistic levels of technology. The setting makes sense because Berserk's world is, for the most part, "real", and the fantasy aspects of the series act as intruders or exceptions.
One chapter had a tagalong "normal" character, a knight in standard plate armor who had cause to ally himself with the group for reasons of self-defense. I invested myself more heavily in this knight than basically any other character because his life and death was of legitimate concern. The realism used in Berserk helped me understand that he was basically a normal man dealing with normal rules - how could he be expected to survive against demons and monsters? When he actually managed to at least hold them off, his victory felt earned because it stayed within the realm of believability. He used his environment and overcame his limitations, he didn't just get a free pass because he was a protagonist. That's the kind of benefit that realism could provide, but Berserk doesn't take advantage of it 95% of the time. The realism in this scenario would create tension for normal human characters, and Berserk keeps putting its camera on plot-armored protagonists.
Power & Contrast
A long time ago I wrote two articles about the concept of hardship in a narrative. The first dealt with the concept of "conflict" as a competition, the second had to do with authorial interference in a character's endeavor. Both of these are relevant to Berserk because on the one hand Berserk tries very hard to justify its main characters' power, and on the other hand it has a lot of scenes where victories feel hollow and pointless. The social hierarchy of characters' "power levels" says a lot about the series and how its different tones harm its overall concept.
While Guts has a lot of really over-the-top victories, for the most part they at least feel earned. Every victory wounds or scars him; he tires and becomes exhausted like a normal man. There's no sense that he actually would die, because he's a protagonist, but it definitely still feels like a challenge for him. It leaves its mark on him, and it's a big deal in-universe. Guts is the best warrior in the world, but it's not easy for him, it's just what he is.
In the same manner, the Apostles are established as being far more powerful than normal men, but they're justified too - they're not normal, they're empowered entities from another world. The fact that Guts is capable of standing up to them is a testament to his experience, skill, and willpower. Both Guts and the Apostles are justified in their power, and the clash between them feels more important because it's built up as two groups (or one group and one individual) whose power makes sense within the world. Furthermore, groups of "normal" humans can overcome an Apostle or even Guts, in certain circumstances, lending some vulnerability to them. Even the other members of Guts' group take a justified secondary role in comparison to Guts, and if (or when) they have abilities that can help in an indirect way, they use them. They're definitely not as powerful as guts, but there's justifications - often magical - for why they're strong enough to hang out with him and not die.
So then here comes these guys:
Puck (the fairy) and Isidro (the kid) are both bad characters, but they're bad for very different reasons. They share the reason that they both break from the seriousness and immersion of the narrative, but they do it in very different ways.
Puck is the primary instigator of the series' annoying references. He makes puns and turns into Yoda or whatever, and that's just sort of...a thing that's there. Like I said earlier, it's basically the Genie from Aladdin: he just sort of does that stuff and it doesn't really fit into the narrative or the world at all. It's purely comic relief, with no real need for explanation. Puck has always been a light-hearted character, but early on he at least served as a foil for Guts when it was just the two of them. Puck was light-hearted and idealistic, while Guts was grim and ruthless. Puck's character turned into a pointless sideshow around the time the other characters (including another fairy) showed up; since they were all basically "lighthearted, innocent characters", Puck really had nothing to do. He's still technically there, but all that Miura can think of for him to do is make funny faces in the background while other people do actual things. He's a bad character because he's just there to make distracting, pointless jokes.
Isidro, on the other hand, is bad because he detracts from the sense of tension in the series. Isidro is a normal kid in very extraordinary situations, and that could easily be used to regain a sense of power balance ("look how weak this normal kid is in contrast to Guts and the Apostles") as well as providing a character who can grow and develop more naturally as the series progresses. However, the fact that he needs to survive every fight means that he ends up being sort of unjustifiably strong or, at least, lucky. He doesn't really receive training from Guts, and while he gets a few little pointers here and there, he mostly seems to be surviving battles because...he's already survived battles. There's no sense of grueling improvement even though there could be fairly easily. He's just plot-armored and that's the end of that. I don't need to see him die, but if you want me to connect to the character, I need to feel like at the very least he's in serious danger and he's got to push himself to his limits to survive.
The problem with the kid characters in Berserk, not just Isidro but the other four major child characters as well, is that they seem way too invulnerable. Like I said, I don't want to watch kids die or anything, but if you have children as characters in a narrative where adults are being torn apart at every opportunity, there has to be an explanation. It stops feeling like "wow these kids are really special", which is what they're ostensibly going for, and starts feeling like "ugh these kids have super-thick plot armor and it's boring". Berserk is a world that should have child soldiers, and yet it has young heroes. It should have Newt, but they gave us Vaan.
The advantage that Berserk has with its detailed system of realism and justified strength is that the conclusions feel natural and don't detract from the story. When you have all this goofy meta stuff, it takes that away. You can't generate tension while also being outlandishly goofy. Humor is fine; if it's done in character, gallows humor can be some of the funniest stuff in the world. "Irrelevant humor" is not. In the commentary for Aliens, which I'm sure I've mentioned at least five or six times in previous articles, James Cameron says that the humor works because they don't "break" from the scenario: they're making jokes in the face of a very real danger that they understand and fear, and that adds weight and drama to their humor. Berserk's humor simply serves as a reminder that it's fake, which is a really bad thing when the rest of the work is there to convince us it's not.
If there's one thing I can still appreciate about Berserk, it's splash panels and background art. Berserk has some really great artwork detailing entire battles, castles, or troop formations with detail on every soldier and civilian in the frame. The problem with it for me is that those things would make for an interesting story - grounding the narrative in the lives of normal people - and it's just a backdrop for a fairly standard fantasy story about a group of mostly-invulnerable wanderers out to save the world. The advantages that realism could provide are neglected, but the realism is there anyways - for looks, if nothing else.
Demon's Souls had a super-powered protagonist of sorts, but it built up to it - you start out normal, and you end up abnormal. Berserk does that with Guts, but then only with Guts. The other characters get minor explanations for their increased abilities, but they're so single-issue ("I have a magic sword now, this makes me the best swordsman ever") that it just feels like a plot convenience to let them continue to hang out with Guts. What I'd like out of Berserk is more characters who feel realistically expendable, even if they don't die. The whole setting is meant to establish what a crappy, grim, unpleasant world it is, and then they sort of wuss out on depicting it when it comes to protagonists. Something more akin to a group of semi-disposable individuals following Guts (who can still be invulnerable, because he's earned it) would help establish the danger present in the world, allowing for some level of attachment and loss within the narrative. It makes the action scenes worth paying attention to; as it is now, I basically skim them. Why wouldn't I? Nothing important's going to happen. What reason do I have to not skip the unimportant pages?
Oh, right, because they look amazing.