Jawhar, the fella who conquered Egypt, founded Cairo, and fought a variety of foes befitting a splendid campaign.
Made a very basic sketch how it could look like:
JAWHAR
Colour: either grey (the dynastic colour of the Fatimids was white but it’s taken by Gaia 
) or yellow (the Caliph’s banner were white and yellow according to some sources)
1. The Slave General
Jawhar’s rise to fame by reconquering Maghreb. The only scenario where we don’t play as Egyptians.
Player:
- Jawhar (Berbers): has a camp west of al-Muʿizz’s capital of Al-Mansuriya. Can’t train vills or build town centers, has to rely on the allies for economic support and obtaining vills. Castle Age.
Allies:
- Caliph al-Muʿizz (Berbers): rules from the Fatimid capital of Al-Mansuriya and provides Jawhar with villagers and tributes.
- Ibn Ammar (Berbers or modified Sicilians?): a Kalbid and the commander of Fatimid forces in Sicily. Following victory over the Byzantines will help the player with naval support; player 2 in the co-op campaign.
- Sub-Saharan tribes (Malians or another Sahelian civ): passive AI in the southernmost part of the map allied to everyone, has a market to trade and perhaps could provide bonus soldiers in return for mini quests.
Enemies → Allies:
- Zenata tribesmen (Berbers): the closest but weakly defended enemy. After their hero Ya’la ibn Muhammad al-Yafrani is killed, they switch to Allies and start providing the player with vills and military support.
Enemies:
- Midrarids (Berbers or Moors): they rule the city of Sijilmasa in the southwest of the map and a castle (Tasagdalt) just to the west of it. Destroying the town center in Sijilmasa switches the control over the city and forces within it to the player, but the castle doesn’t surrender until the hero unit Muhammad ibn Wasul is killed (if not killed in the city, he’ll garrison the castle).
- Umayyads (Moors): the most formidable opponent holding the heavily fortified city of Fez. To force surrender the player needs to destroy castles and town centers, after which the city and units within switch to the player.
- Byzantines (Byzantines): hold parts of Sicily. In case they defeat Ibn Ammar, they will harass Jawhar from the sea.
After the three enemies in Maghreb are subdued (plus Byzantines if playing co-op), we get a cutscene showing how Jawhar and al-Muʿizz are visited by disgruntled Egyptian nobles asking for military intervention.
2. The Conqueror
Title says it all.
Player:
- Jawhar (Egyptians): begins with a decent army and navy at a Tunisian Port (this site claims it was Kairouan, but Kairouan is inland…), can advance to Imperial Age after taking over Alexandria.
Allies:
- Caliph al-Muʿizz (Berbers): holds a port in Tunisia and supplies Jawhar with tributes from time to time.
- Ja’far ibn Fallah: Jawhar’s subordinate who establishes small camp outside Alexandria following the successful landing and can attack in flared directions. Player 2 in the co-op.
Enemies: - Ikhshidid navy (Egyptians): most dangerous early on as they can sink Jawhar’s transport ships if the player is not careful. They hold the Nile Delta and initially Alexandria, but the latter immediately switches to the player’s control after a successful landing. Destroying their docks and military buildings scattered in camps across the delta forces them to surrender and awards the player with extra transport ships.
- Ikhshidid army (Egyptians or Turks without guns): holds the heavily fortified Rawdah Island and other camps scattered across the map.
- Hasan ibn Ubayd (Mashriqi): based in Palestine in the northeastern corner of the map, the most powerful opponent if unchecked for too long.
Neutral:
- Locals (Egyptians): they hold a number of towns across the map, each with a tower at the center; converting each tower grants the player control over its town. The biggest, Fustat, doesn’t have towers, it switches to the player’s control after the conquest of Rawdah Island.
3. Viceroy of Egypt
The goal is to thwart the Ikhshidid remnants across Middle and Upper Egypt, subdue Nubia and Hejaz through military or diplomatic means, and build a Wonder (al-Azhar Mosque) in Cairo.
Player:
- Jawhar (Egyptians): controls the northernmost corner of the map (Cairo). There’s not much resources in the vicinity and a huge part of Cairo is not available to be built on (it’s reserved for the Wonder) so staying there too long is not recommended. Starts with a hero monk al-Aswani whose death ends with the mission’s failure (in the co-op version al-Aswani would belong to a separate player alongside a couple vills and a packed Town Center).
Allies:
- Ibn Hinzaba (Egyptians): former Ikhshidid vizier who switched allegiance to the Fatimids. Holds Fustat directly south of Cairo but initially lacks resources and needs to be defended from Ikhshidid remnants (his defeat equals the player’s defeat). Gives out side quests that can be completed for extra technologies and troops.
Enemies:
- Ikhshidid remnants (Egyptians): various bandit camps across the map.
- Beja tribes (Egyptians? Nubians? Arabs? Berbers? Somali?): their camps block access to the Red Sea and the Musawids across it.
Neutral → Allies or Enemies:
- Makuria (ideally Nubians, but if for some dumb reason Saracens are split before adding more African civs then Ethiopians would suffice I guess): has a very strong base in the middle portion of the map.
- Alodia (Nubians or Ethiopians): southern portion of the map.
(Both Nubian factions need to be either significantly weakened militarly or visited by al-Aswani and bribed with food, after which they’ll supply the player with gold and Archers of the Eyes) - Musawids (Arabs): controls Hejaz in the southeastern part of the map across the Red Sea. Needs to be conquered or bribed with gold.
4. The Qarmatian Invasion
Jawhar’s subordinate Ja’far ibn Fallah pushed into Levant with initial success but suffered catastrophic defeats at the hands of Byzantines and Qarmatians. He died in battle against the latter, the Fatimid possessions in Syria were reduced to Jaffa, and Jawhar was forced to defend against the Qarmatian onslaught.
Player:
- Jawhar (Egyptians): controls the city of Cairo at the bottom of the map and needs to defend its Wonder (Al-Azhar Mosque).
Allies:
- Jaffa (Berbers): remnants of Ja’far ibn Fallah’s Kutama army and Jawhar’s relief force barricaded in Jaffa in northern half of the map. They might slow down the Qarmatian onslaught and Byzantine raids for awhile but they’ll almost definitely fall without the player’s support. Player 2 in the co-op.
Enemies:
- Qarmatians (Arabs): holds the heavily walled city of Ramla east of Jaffa and a number of strong palisaded camps across Lower Egypt. Will send wave after wave to besiege Cairo, but each destroyed camp lowers their numbers. Destroying either all their camps or recapturing Ramla wins the scenario.
- Egyptian rebels (Egyptians): bandit camps scattered throughout the map
- Byzantines (Byzantines): docks and fire towers in the northernmost part of the map, uninvolved on land but undisputed naval dominance in the Mediterranean. If unchecked will send dromons down the Nile to annoy the player.
5. Dunno, I’m too bored to finish this post
Jawhar’s final campaign in Syria with Arabs, Turks, Mashriqis and Persians (Buyids) as enemies.
6. Byzantine Empire Strikes Back
Elderly Jawhar doesn’t partake in warfare anymore but narrates the events of the Fatimid war with John Tzimiskes.