Dimensional Travelers

"This world has been connected...tied to the darkness...soon to be completely eclipsed...there is very much to learn...you understand so little...a meaningless effort...one who knows nothing cannot understand nothing."

- Ansem (Xehanort's Heartless) to Sora

A Dimensional travelers is any character who can (more or less) freely travel between various planes of existence, like parallel universes, etc. Their ability to travel is usually powered by an Interdimensional Travel Device or some form of magic, but it can also happen that a character was inherently born with such power. This is also a common explanation for Crossovers, as occasionally the characters will arrive in the universe of another hero. A possible practical application of this power is to make use of Extradimensional Shortcuts. Distinct from Time Travel because, although Time is considered the "fourth dimension", time travellers otherwise remain in the same plane while hopping between its different time periods.