Masterverse: The Nature of Time

Time
Time first began ticking when the Universe was formed, when Earth began to take shape, Arceus created Dialga to guard time and Palkia to guard space. Time is infinite and endless as the universe, so long as the universe exists time will continue to flow. Due to how time is so interconnected into the integrity of the Universe, it is classified as one of the 5 Legendary powers of the Universe alongside Space, Antimatter, Life/Death and Creation. It is often said if one controls at least one of these powers, they control everything.

Time-Travel
The ability to travel up and down the river of time is a rare ability that only Dialga and the Celebi are known to have. Normally this ability is impossible to replicate purely from science alone, however if one acquires an object or artifact related to time such as Dialga’s Diamonds or a Time Gear, such a machine could manipulate the temporal powers within them for coronal displacement. However even if one manages to do this, their actions may not go unnoticed as Dialga can sense changes in the timeline. So unless you plan to use time travel just for sightseeing, better be sure you know what your doing.

Adjacent Timelines
While the multiverse encompasses the various parallel worlds, a single universe supports the multiple timelines that spawn within them. While time itself can be compared to a river, timelines are likened unto tree. The trunk represents the main timeline and its closest siblings, while the branches represent splinter timelines that form the unlimited possibilities that can happen. That being said, while their are an infinite number of possibilities, the universe itself only has the energy to support a select number. As such at certain points a Quantum Time-Lock(see below) will occur which culls and erases timelines that have been selected for culling. A timeline can be culled for several reasons, most of which include: Deviating too far from the Main Timeline, advancing too far into prosperity or stagnating to the point of decline and ruin, the past of a timeline can no longer be undone, the timeline’s inhabitants can no longer meaningfully impact the future. In very rare cases, a timeline has the potential to break off from the tree and form its own adjacent universe should it accumulate enough energy and survive multiple cullings. The timelines with the most potential for this are the ones that are closest to the Main Timeline.

Quantum Time-Lock
Due to the dangers of how time-travel can change and alter the timeline, Dialga and Arceus once used enforcers to deal with individuals who would mess with time, this group was known as the “Time Masters” and they were tasked by Dialga to protect the timeline and correct any aberrations to history. However the Time Masters eventually became corrupt and began to manipulate the timeline for their own purposes, their actions were soon discovered once the event know as “The Second Timewave” occurred. The Time Masters where “dealt” with and Arceus decided to implement a new way of protecting the timeline. This became know as Quantum Time-Locks, points in time which are unaffected by changes in the past or future. The way Quantum Time-Locks work is that certain events or phenomena that exist within the purview of a Time-Lock are cemented permanently. So if one were to move to a chronological position in the past of an "anchoring band" to the end of modifying history, as time progresses unto the Time-Lock, history would be forcibly corrected to its state of record. Example: lets say that a war happened in Equestria and the "outcome" was that "Equestria was destroyed" is secured as a matter of record. In the circumstance that changes history wherein "Equestria is spared; its war is avoided; and its people live in peace and happiness" is successfully brought about, in the moment that history advances unto the anchoring band, the outcome whereby "even so, Equestria meets its destruction" manifests. You may be able to save a few or any number of lives. However, modification to the overall course of History is decisively beyond possibility.