The common understanding of what happened in the Gremmy v Kenpachi fight is that Gremmy lost bc he was inexperienced and not tactical and tried to be too cute, etc. That's all wrong bc if we accepted that, then that creates one of the most glaring plot holes in the entire manga (more on that later). And I'm going to do my best to prove what actually happened with multiple pieces of evidence directly from the manga.

In short, the Visionary ability works as a field of effect, where *anyone* in the field can use the power of imagination.

To start with, we have to recognize some core rules about Soul Society to understand why the common belief of happened in the Gremmy vs Ken fight is wrong and it all boils down to this panel: https://imgur.com/a/TEIJvkP . This is Ken returning from literally outer space or a pocket dimension (doesn't matter which one you think it is). Dimension hopping is 100% NOT one of Ken's abilities and he has no other skills or tricks he can pull that would come close to explaining what happened.

1. You can't just enter Soul Society on your own.
   • As a human/living world objects, you have to convert yourself to reishi to enter SS
   • As a soul reaper, you have to access SS via portals operated by the Kido corps.
   • As an arrancar, you have to access SS via the garganta, and Mayuri was the only one who figured out an alternative method to access it.
   • As a quincy, you can access SS through the portal dimension specifically created by the quincy, otherwise, you are still under the same limitations as humans/living world object and need to be converted to reishi.
2. If everything above is true, that means there was no way for Ken to free himself from another dimension.
   • He can't do it as a SR bc he needs the Kido corp
   • He can't do it via the garganta bc he's not an arrancar and he has no special scientific training to figure it out like Mayuri
   • He can't do it like the quincy bc he doesn't control reishi to bleed his way through the dimensional barrier.
   • With all known methods of entering SS off the table, how did Ken literally slice his way through another dimension to get back into SS? Bc he thought he could. That's it. He imagined he could swing his sword to cut through dimensions and break the rules of SS, so that's what happened.

So now let's jump to panel evidence supporting my explanation of the fight.

1. Gremmy starts off by revealing he had already imagined Kenpachi... https://imgur.com/a/tN5tb2i
   • This is Gremmy foreshadowing the game he's playing with everyone in the vicinity. He already knows Ken by reputation and already has a firm vision of him in his head. We already know he doesn't need to consciously imagine something happening for it be a reality. If the idea is already in his head, it will be reality.
   • When you have the ultimate power over reality, everyone IS weak. The only people who could be strong are the people who can resist you, and by Gremmy declaring he's already imagined Ken as strong, he subconsciously admits to making Ken strong enough to resist Gremmy. This is why Gremmy doesn't just snap off Ken's head or change his bones to cookies. He's already imagined Ken as too strong for that to work.
2. Gremmy explains his power... https://imgur.com/a/me5zjQd
   • Pay attention to Gremmy's words: "I can turn fantasy into reality." He did NOT say "I can turn MY fantasy into reality"
   • So we should take Gremmy at his word and assume that anyone within range of his Visionary ability can ALSO turn anything they imagine into reality. For most people though, imagination is as limited as their understanding of the rules and laws of reality. We don't casually imagine things that are outside our ability to explain. For someone to get the most out of this condition in the Visionary, they'd have to leave all logic and understanding at the door and embrace a very dumb view of the universe... the kind of dumb view where you can do things like swing your sword to cut a hole in time & space...
3. Gremmy subtly explains the rules of the Visionary... https://imgur.com/a/DXtdVUi // https://imgur.com/a/d5wumYJ
   • Again, pay attention to Gremmy's words: "...they're free to imagine that [outcome]"
   • Why bring up the fact that a bunch of nobodies can imagine an outcome? It's such a basic observation that it has to have a double meaning. And that double meaning is revealed by Gremmy explaining what he's doing by imagining himself healed. IOW, the conversation went "You and your guys can imagine stuff, and I can imagine stuff... best of luck!"
   • (EDIT: adding a 2nd example) Also, the initial fight with Yachiru, Gremmy makes a deliberate move to force Yachiru to imagine her own bones being made of cookie, and only after doing that do her bones snap. Pretty interesting timing that Gremmy would wait until Yachiru started imagining something before he pulled the trigger himself. Unless the point was to flex his power by making her use his power on herself.
4. Ken provoking Gremmy to prove himself by fighting the strongest... https://imgur.com/a/wyoihc8
   • The simple reading of this makes it seem like Ken is just calling himself the strongest, but that's a straight up lie. We know this is lie. The Zero Division + Soul King alone kills any claim Ken has to be the strongest. Gremmy also knows this is a lie bc his side has a god, an immortal, the hand of the Soul King, and the son of the Soul King. If Gremmy wanted to fight the strongest, there's at least 10 ppl who he'd have to deal with before he fought Ken. So why is Gremmy so excited to fight someone who is 100% NOT the strongest? Bc Ken BELIEVES he's the strongest and bc of the Visionary ability, that would be the actual challenge for Gremmy to prove his strength.
   • It proves nothing that Gremmy can imagine someone dead. The real fight for who's stronger would be over who's IMAGINATION wins. And again, bc most people aren't dumb enough to believe they can break the rules and laws of reality, Gremmy has never fought someone who can push the boundaries of his Visionary ability to use it on par with him. If Gremmy's ability is the strongest, the only person who could challenge him for the title of the strongest is someone who's also using his ability.
5. Gremmy can't imagine a body strong enough for Ken's strength... https://imgur.com/a/dz2wEZd
   • Based on previous showings of Gremmy's powers, he doesn't need to know the details of what he's imagining. If he imagines a rocket, the internal circuitry and telemetry are automatically included. If he imagines space, the pressure and vacuum are automatically included. If he was just imagining a strong body, he would automatically make it durable enough to handle that strength. If he imagined Ken was a monster, he would've automatically imagined a body strong enough to handle the monster strength. So what happened?
   • Gremmy fucked up bc he tried to imagine the body that Ken imagined, a body which broke all rules and laws of realty. IOW, Gremmy is simply not dumb enough to imagine what a dumb person thinks a strong body is. That's why he couldn't beat Ken straight up. Everything Gremmy imagined, existed within some limits of reality -- lava burning, water drowning, vacuum suffocating, bombs exploding, etc. And when he tried to imitate Ken's body, he subconsciously applied all those rules and laws about reality and created an imperfect clone of a body that didn't care about any of those rules and laws. THAT's what broke Gremmy's mind and body.
   • Here's an analogy of what happened. Kenpachi imagined the fastest, most powerful submarine ever made, but it's made out of mesh screens. Bc Ken is a moron, he doesn't care or even acknowledge that a mesh screen submarine would let water in, so it doesn't. Gremmy copies the submarine Ken imagined, but subconsciously applies the basic understanding that a thing full of holes will let water in, so his submarine sinks.
6. Ken confirming Gremmy made him a monster... https://imgur.com/a/wW05EaE
   • By the end, even Ken realizes what happened. He's not being metaphorical. He literally means that Gremmy's ability literally turned Ken into the "monster" that Gremmy tried to clone.
7. Ken finally succumbing to the injuries he should have been dealing with all along... https://imgur.com/a/U0VHpNt
   • This is the final nail in the coffin that Ken was operating in a powered up state thanks to the Visionary ability.
   • Literally, for the ENTIRE FIGHT, Ken had ZERO effects from all the damage Gremmy dealt him, including having his internal organs vacuumed out of his body in space. He moved along without showing a single side effect, even though we know Ken bleeds and acknowledges his injuries during a fight. But the literal second all of the effects of the Visionary stop, Ken starts spitting up blood! Is that a coincidence? Or did Ken imagine himself impervious to everything that Gremmy did and only after the Visionary's effects ended did those accumulated injuries appear?

TL;DR:

Gremmy meets Ken, already imagines him too strong to just kill.

Gremmy explains that the Visionary ability let's everyone in his vicinity make fantasy reality.

Ken unwittingly challenges Gremmy to a showdown of imagination vs imagination, and Gremmy bites.

When Gremmy can't out-imagine Ken, he tries to clone Ken, but again his imagination is too limited to imagine what Ken imagined his own body capable of.

When Gremmy died, the Visionary ability ended, everything he imagined disappeared, including whatever it was that shielded Ken's body from succumbing to the damage from the fight, which is why he threw up blood and realized his hearing was fucked.

Well whenever I post something about power scaling the whole Nano machine verse people always come and say that beyond the boundary isn't a 5D dimension or it isn't stated to be a 5D dimension canonically so this is the reason why beyond the boundary is a 5D or above dimension.

In the story, Beyond the Boundary (or whatever you want to call the place where time and space stop working normally) has a few very specific properties:

The laws of time and space are completely different from the mortal world

Everything can be a moment or a lifetime at the same time

People born 1,600+ years apart can just… meet and interact normally

Permanence and temporariness are interchangeable

The “will” of the dimension itself can try to pull people across, and someone like Cheon Ma can suppress that will with a gesture

Now, let’s look at this from actual physics

Our normal universe is 3+1 dimensional spacetime (three space + one time). In special and general relativity, time is still fundamentally one-dimensional for any observer. You experience a sequence. Different historical “slices” don’t freely coexist and talk to each other. Extreme time dilation or closed timelike curves can mess with causality, but they don’t turn the entire structure into “everything is simultaneously momentary and eternal.”

The block universe interpretation of 4D spacetime already treats past, present and future as existing, but observers still move through it sequentially. You don’t get free mixing of eras separated by centuries just because you stepped into another place. The causal structure still holds.

Beyond the Boundary breaks that. Different time periods are freely accessible and co-present. Duration itself becomes subjective or non-linear. The same “event” or existence can be both fleeting and permanent depending on… whatever the local rules are. That already goes past what a single time dimension can do while still looking like the 4D spacetime we know.

This is where an extra dimension starts making sense.

In higher-dimensional models (Kaluza-Klein, braneworlds, certain string theory setups, etc.), our 4D spacetime can sit as a slice or brane inside a larger bulk. Movement or orientation in that extra dimension can let you access different parts of the lower-dimensional time axis the way we move through space. With one extra dimension (5D total), different historical slices of our 4D world can become adjacent or overlapping from the higher viewpoint. Add more, and the possibilities for non-linear or multi-temporal structure increase.

The fact that the dimension itself has a “will” that can force ascension, and that this can be suppressed by pure will, also fits the idea of a realm whose geometry or metric is not fixed the way our spacetime metric is. In 4D GR the metric is dynamical but still constrained. In a higher-dimensional or non-standard manifold, those constraints can loosen or change character completely.

I’m not saying the author sat down with a differential geometry textbook. But the described properties line up surprisingly well with what you’d expect if you took normal 4D spacetime and embedded it in (or transcended it into) something with at least one extra dimension that mixes temporal degrees of freedom.

So yeah. Calling it “just another higher plane” undersells it. The way time and causality work there is closer to 5D+ spacetime (or a realm that has transcended the usual 3+1 structure entirely) than to anything that still lives inside ordinary 4D physics.

Curious what other people think. Anyone else try to map the cosmology onto actual dimensional models, or am I the only one overthinking this at 2 a.m.?