The Negative First Causal War was the -1st conflict to involve the Apeirocoalition and the Guardians of Aleph fighting over multiple timelines and timesquares. Although it took up merely an immeasurably small fraction of the Omniverse, it involved the combined armed forces of numerous high-level archverses and an extremely large number of cosmic entities, deities, and other beings.
Background[]
As the Apeirocoalition spread throughout reality, unifying civilizations as it travelled and continuing in its mission to create a permanent bastion of order in the omniverse, it ran across a set of protoverses requisitioned by the Guardians of Aleph for archival and storage purposes. An Apeirocoalition scout fleet of several billion galaxy-sized spacecraft intruded into the Interdimensional Void surrounding these protoverses, alerting the Guardian of Aleph known as Kzkzt'thtrerther'thaz. This entity, who was only at a low multiversal scale of power in the Cosmic Entity Tiers, called for backup in an effort to "purge" the intruders. This began the war.
Combatants[]
It is believed that the Guardians of Aleph, despite already being infinite in number, called upon an even greater infinite quantity of reinforcements. These included, among an arbitrary number of other things: Kardashev Type-Infinity civilizations (which control infinite amounts of energy), numerous gods, and objects similar to the Idea Breakers though on a much smaller and safer scale.
Similarly, the Apeirocoalition had an endless supply of forces from its own Kardashev Type-Infinity (and lower) civilizations, Boltzmann Brains, mobile -verses, metamesonium bombers, and countless other sources.
War[]
The Apeirocoalition's most powerful members violated causality and deployed their most powerful superweapons before the war actually started, without causing their own deployment. Numerous high-level -verses were cut off from the rest of existence, destroyed, or had their laws of physics torn apart by the barrages from unimaginably powerful weapons. Time itself split apart, and many of the war's early battles took place on battlefields that rapidly diverged as separate possibilities folded up on themselves into new -verses. In other words, it was utter madness for the typical non-omniscient observer.
To take advantage of the disintegrating timestreams, the Guardians of Aleph enlisted countless elder deities and Cosmic Entities to forge a set of battlefield timesquares: these were -verses in which time flowed in two perpendicular directions, so one could turn around and face their own past, or move side to side along different extents of time. With this advantage, they were able to repel many Apeirocoalition fleets by outmaneuvering them in both space and time.
The war split off its own segments of reality, and centillions of years passed within milliseconds in some of these. In fact, time became so mangled that it is believed the war was actually infinite in duration, taking place at all points along whichever timelines hadn't been destroyed.
Manipulation of Casualty[]
Entities can manipulate causality, the relationship between causes and effects, allowing them to decide what happens and what does not, when and how. But, there is no need for a "why", as the why of something is determined by causality itself, which is under the command of the entities, making it one of the few powers that do not need a reason. Specific changes are momentary, ceasing naturally with their realization, i.e. the Absolute Will. Systemic alterations permanently change the causal structure of reality, imposing new chains of fate upon it until the user decides otherwise. All forms of existence and phenomena depend on causality. For this reason, the power to manipulate it naturally outweighs any other power against it, as they all depend on causality to function. Beings that overcome cause and effect completely bypass any law of logic, manipulating it without limits, are beings that are not limited to cause and effect, being conceptually more powerful than that, is completely illogical, an unlimited power over choices over everything that exists. Not only choices, but a manipulation over all motives of everything, being just an insignificant concept to them.