Duel Galaxies Universe

Duel Cloud Yugiverse is a fanon Yu-Gi-Oh! series. It is defined by a multitude of interlocking protagonists and cards that all occupy different worlds.

Its action is primarily defined by three separate realms, the "Main" realm, the "Card Plane" realm, and the "Cloud" realm. The main realm is a seemingly regular world (as far as Yu-Gi-Oh! worlds go, e.g. dueling is a prominent competition), and possesses what seems to be most if not all of the card game, including all of its various summoning methods. Occasionally though, entities and cards from the other realms appear and influence the destiny of the main realm. Meanwhile, the Card-Plane realm also features most if not all of the cards, save here the cards are not cards, but actual creatures, actions, objects, and events. They are not "spirits" or anything such as they were in any previous Yu-Gi-Oh! series, however; here there is probably indeed a "Tactical Espionage Expert" living a life as a "tactical espionage expert".

The Cloud realm is divided into many, many distinct worlds. Usually, these separate worlds are referred to as "arms". These arms are defined by duelists who all use the same stricter version of a summoning method: for instance, in the Super Arm, all the duelists conduct Fusion Summons via the effects of their own personalized "Super" fusion cards, from the protagonist arm Yuco with his trademark "Super Collider Fusion", to one of the many antagonists, Baron, with his deadly "Super Dark Fusion".

There seem to be Fusion, Synchro, XYZ, Pendulum Link, Ritual, and even Token (!) arms.

Sometimes the barriers between the worlds are not very clear: for instance, the "Nner-blade" monsters seem to be denizens of the main world after having somehow crossed over from the Card-Plane realm, whereas the "Chaos X" monsters in the Cx Arm controlled by opposing duelists are also clashing factions and fighters in the Cloud realm.

The Card Plane Realm
In the card plane realm, the characters and entities "depicted" in the cards in other realms are actual entities. DCY tends to not focus on the events in this realm to too great a degree, majorly excepting when the conflict or villainy in one or both of the other realms is driven by entities from the card plane realm.

Fusion-related
sF Arm (the Super Fusion world):

Synchro-related
tS Arm (the Transcendental Synchro world):

Xyz-related
cX Arm

xA World

xM-ade (Material Attach-Detach Effect world) actually part of a binary world with xM-scad

xM-scad (Material Summon/Cost Attach-Detach world) actually part of a binary world with xM-ade

mC (Material Construct World)