World Mechanics - Realms

Dimension (Realm, World)

A plane of existence
Each plane is given an arbitrary number, generally given in order of discovery. Exceptions to this are the third and 0th realm, the third realm being named after the number of perceived dimensions in the world, the 0th realm is named such because it is thought to be the origin of all realms.
Magic occurs when another realm is accessed. In the third realm, magicians reach out to other realms to cast magic; when they do so, they temporarily overwrite nature and physics of the third realm with the realm of another world.

A majority of magic is drawn from the 0th realm.

To put it simply, a world is just a parallel dimension. There are infinite parallel dimensions of an infinite amount of permutations in stOP, and each dimension is self-contained. For the most part, at least.
In the case of Earth, or the 3rd realm, it is possible to access other dimensions, albeit briefly. Doing this allows somebody to bring some power from another realm. Essentially, this allows a person to superimpose a reality that isn't Earth into Earth. Some worlds conform to different physics, where things such as casting fire or speaking to animals are commonplace.
A magician is a person who can access this world, bring its reality to Earth temporarily, and then control that reality to cast some sort of magic. For Earth, most magic is drawn from the 0th realm, as it is the easiest to access and the most malleable of the realms.
Back to dimensions... dimensions are not strictly 'parallel worlds' or 'parallel earths.' It is easier to think of each dimension as a collection of rules that form a world or a universe. For instance, there can be realms that exist that are only one dimensional, or realms that are completely dimensionless, or realms that are composed entirely of other realms.
These realms also need not have any semblance to Earth's realm. It is possible there exists a realm where organisms live in space, and living on a planet is seen as impossible. There can be a realm where time runs backwards, or a realm where color doesn't exist. There's really no limit to what a realm can be, although within the scope of most stories in stOP, a realm will be an Earth-like world with properties that aren't Earth-like.

Ultimate Throne

Multiple kingdoms are at battle with each other, forming strong alliances and betraying weakening ones. Among their armies are knights who have learned the largest of all kingdoms, Atlasia, has announced a call for truce. Many kings and queens protested, but as the majority took to the call, the raging war came to an end.

Many knights were later persecuted for their crimes in battle, even though they were sworn to command and secrecy by their respective parlaments. One of them was unable to tolerate such blashpemous behaviour by the pulic, and demanded retribution by the ultimate king's septor. The king, however, refused, and this caused the first crack in the knight's mental armor.

Unable to reconcile with society, he decided to kill the king, steal the septor, and escape to form his own nation. With news srpeading to the other kingoms, all the knights were ordered to seize the septor, as it would represent a new era of leadership among the crowns. Little did they know that a guild of warriors possessed by a mysterious warlord were given to this knight, who has been told by a sage that the septor was in fact an artifact to summon divine power.

Each knight was given the strongest weapons and spells their castles could store. Each one a pallete formed by their valor, they ventured into unmarked lands to gather knowledge of the ex-knight. All the while, the heir to the ultimate king's throne was attempting to calm his people, enraged by their successor's inability to take action against the ex-knight. As a pacifist, (he/she) never took anything personal by his action, realizing that being marked a monster will only provoke a mind to behave as such. That being said, the septor was a keepsake by his/her father, and wanted it back. Learning about a warrior who slayed a dragon in a far away country, she/he calls for his helping hand in return for a seat on the throne (the warrior would be male/female either to resolve this).

The warrior refuses, calling it a hassle to jump in a turmoil brought by the people. The heir does not plead, and attempts to provoke his pride, claiming his valor is nothing more than rumor. This works, as he decides to find the knight in return for information regarding a man who murdered his mentor.