The world inside the arena changed, at least, for Crimson Inferno.
In truth, from an objective point of view, everything looked the same. In fact, Kyle's Momentum didn't even oppress the Energy. The Energy just kept moving as if nobody had activated their Momentum.
Momentum originated from someone's mind. The power, conviction, and confidence people built by emerging victorious from one instance of adversity after another created a force that changed their surroundings.
However, that was only true for raw Momentum. Unrefined Momentum.
Raw Momentum was like an explosion without a gun barrel. It had force, but it wasn't guided and simply expanded outward without guidance.
Since Momentum originated from someone's mind, it could also be guided by someone's mind, but it wasn't possible to guide it just because someone wanted to. Without a body, a person couldn't pick up an object.
