DC123456789
Deity
However, since you must pry, we will not fight on your behalf for two reasons. Though we do not not condone the destruction of the Coptic Church by the Muslims, we have examined the events leading up to the declaration of the crusade and hold the Copts to be the general cause of the war, by invading the Fatmids.
The war actually started 200 years earlier. It is important to note that the Kingdom of Makuria was a Coptic state, allied with Axum, that was conquered by the Fatimid Caliphate.
From update 0
Deep in Africa, where Islam has yet to fully penetrate, lie two remnants of antiquity. The Kingdom of Makuria is the last remnant of the Nubian civilization that once rivaled Egypt itself, but as a Christian realm it is deeply threatened by the Fatimids and its days appear numbered. South of Makuria lies the Kingdom of Axum, an Ethiopian nation and Christianity’s southernmost frontier. Axum seems better prepared than Makuria to hold off a future Fatimid assault, but it too has grim chances of survival.
Though not stated, it is inferred that the Fatimid Caliphate was at war with these two countries.
From update 1
The Fatimids quickly overran Makuria. However, in a last-ditch effort to salvage his country, the king of Makuria accepted vassalage to the Fatimids if he kept his lands, with the exception of the coast, and was allowed to maintain Coptic Christianity as an accepted religion. The Nubian civilization lived on, if subjugated. The Fatimids themselves are preparing to move on to their next target, Axum; but Axum will not be so easy to conquer, as they
Here, you can clearly see that the Fatimids were the aggressors in this war. One could also infer that they declared war, as the Coptic states would never have done something so dumb. Also, in our timeline, (which happens mostly accurately until the NES starts), the Muslims attacked first.
From update 3
Muslims began settling to the south in North Africa, farther inland from the coast, although the highly arid climate placed a hamper on the expansion. The Fatimids completed a road network along the coast and banks of the Nile River, boosting trade. By Caliph’s act, Makuria was seized; its lands fully annexed, its vassalage disbanded, and its people absorbed – with all the effects that brought.
You can obviously tell that the Fatimids are imperialistic aggressors from this act. It is also inferred that the Nubians rose up here (see the map).
Your evidence that the Copts started the war are based on Axum's reclamation of Makurian lands. This is like saying that Britain was the aggressor against Germany in WWII in our timeline, with Britain being Axum, Makuria being France, and the Fatimids being Germany. Rather, they were liberating the Copts from the occupying power. They even reinstated the royal family of Makuria:
From update 7
The war for the Nile continued. Despite an attempt by Axum to bolster its defenses by allowing the old Makurian royal family direct control, the Zengid Emirate sent nearly its entire – massive – army to help defend the Fatimid Caliphate. Not only were the Zengid foot soldiers greater in number than the Ethiopians, they also were of greater quality and training, something that would prove decisive in this war for the Nile.
They even offered peace, and a perfectly fair treaty that would have seen Muslim lands belonging to Muslims, and Coptic lands belonging to Copts, essentially a status quo ante bellum:
From: The Kingdom of Axum
To: The Fatimid Caliphate
Our nations have suffered greatly as a result of the wars that have been raging throughout the last 200 years. War has ravaged the lands of the Nile. We offer you a truce. Will you accept?
From: The Kingdom of Axum
To: The Fatimid Caliphate
What is your "rightful land"? We will happily retreat out of Egypt, but Nubia will never fall under the influence of muslim infidels like you.
OOC: Sorry for the rather late reply, I missed this earlier. Also, sorry <nuke>, but I simply cannot let this go unchallenged. I'm also itching to roleplay the Axumite government-in-exile to conduct diplomacy.