Why Yami actually should be scaled to Dimension Slash.
So, this post will go over why Yami should be scaled to what he destroys through Dimension Slash. This argument came from a friend of mine. My argument for why Yami scales to Dimension Slash is rooted more into what a hax is in the first place, what can be scaled and scaled to in the first place, and why someone should or shouldn't scale to their hax. But that's enough about my idea. This post presumes you know and understand the argument of Glamour World being infinite in size and Yami destroying it through Dimension Slash in the anime in episode 151, which Tabata supervised.
Firstly, let's establish something about dark magic. It is the complete opposite of light magic. While light magic is absolute in speed, dark magic, being it's opposite, would be extremely slow in comparison.
Licht explains how Yami is able to keep up despite dark magic being extremely slow in comparison to light magic. The reason dark magic is even able to keep up in speed with light magic is because Yami uses his physical force, amplified by magic power, to speed up his attacks.
Now, what is Dimension Slash slash? Dimension Slash is a strand of darkness that has spatial cutting properties. That's all.
After Zagred's Underworld spell leeched Yami's life energy out of him, Charla(the elf possessing Charlotte) healed Yami's arm. Only then did Yami say he can handle another Dimension Slash. Even when he uses Dimension Slash, he still requires his physical strength to use it in the way he does.
Yami also used the force he generated through DS to halt the boulder that Dante threw at him at high speed, proving again that if it didn't have AP, the force of the attack wouldn't have been negated, and the boulder would still be moving. This shows once again, just like any other slash Yami has, it generates power and would scale to him.
So, what about Dimension Slash Equinox, the attack used to destroy glamour world now does he scale to it? Yes, Yami would scale to it because what DSE comes from is using mana zone to generate a single strand of darkness with more magic power than Yami can normally produce. In the Glamour World fight case, Yami generated an infinite strand of darkness that traveled across the infinite space in finite time, which not only allowed him to cut the entire space, but also destroy it. We know it traveled due to it affecting both crystals during the captains match, too. So, yes, Yami would also have infinite speed since its speed would depend on Yami in the first place.