In the lands of Ninewah (north Iraq).
The rebellion of Musawir which captured the city of Hulwan wgich started as a simple protest against unjust execution, had turned into a fearsome army now free to roam the most north sections of Iraq. It's leader, Musawir ibn abd al-Shari, a tribal Arab Shaykh who in his early days served as a minor general in the Abbasid caliphate and gained notoriety in early battles with the Khurramiyyah in defending Arab tribal territory. However, originally a Sunni Muslim of strong faith, over the years with the Mihna and the corruption in the Abbasid court and the obvious disagreement between a man considered a hero, Yaq'ub al-Saffarid and the Caliph Mu'Tazz who more and more was seen as weak, led him to begin to rethink his views on giving Bayait to the caliph and considered the path of the rebel in accordance with factions in his court made up of Khawarij.
A famed horseman, one of the major figures in this conversion of Musawir, named Muhammad ibn Qurzad, a Kurdish Khawarij. A man of extreme deceptive abilities, he considered himself to be a master of secrets and performed kitman to its upmost perfection. He from the start inserted himself in the court of the Dhiqan Musawir to incite a rebellion eventually primarily of Kurds, especially those disaffected from the Khurramiyyah and the atrocities committed previously by former caliphs. Qurzad in his manueverings attracted fellow Khawarij inciter, Ayyub ibn Hayan al-Wariqi, a Arab tribesman from Egypt previously of Coptic faith, to the court of Musawir in al-Bawazid, near the city of Hulwan (near Mosul).
Ayyub ibn Hayyan and Qurzad at the onset of the revolt became the trusted commanders of Musawir and directed the aged Shaykh further into war, all the while attracting warriors from the Kurdish tribes to their ranks. The two would also become the mouthpiece for Musawir who assumed the role as ceremonial leader and general in the field. However, the coordination was beset by a deep seated mistrust as always followed the deviancy of the Khawarij, a lust for power always sat at the hearts of the rebellion which said that the rule is for Allah.
In the same year, Palestinian strongman, Isa ibn al-Shaykh al-Shaybani tasked by the Abbasid court for the leadership of Ninewah and Anbar tribal areas, arrived in Hulwan to asses the damage.
Speaking to his aid, Kamal al-Fustayd
"This Musawir, who exactly is he, and from whence did he come?" Said Isa
"Surely you recall him, master? The man of the hill country, he served for years in the Zanjan heights as a lieutenant engaging the Kufr of the Khurramiyyah."
"Wallahi (I swear), his past matters not! It matters not if he was the son of Muhammad (SAW) himself, I will cut him down in the valleys and the hills and in the vast desert to which he flees my swinging sword. Age hath corrupted a man of supposed virtue, thus let I be the cleansing water to which his deviancy is eradicated. I, have yet been bested in war nor in faith nor in debate, let he fear thy which have none!"
Kamal al-Fustayd (always seeking to kiss up) thus replied:
"O assuredly, battle is a problem, not for thee. Verily, let the enemies of the string sword cower as women below their husbands, let them shreik for the awaiting massacre."
Then in an almost ghostly manner, a messenger arrived with a letter for Isa ibn al-Shaykh al-Shaybani.
The letter was thus opened and read aloud to Isa ibn al-Shaykh al-Shaybani (illiterate) by Kamal al-Fustayd, saying:
"Greetings, we bid you glad tidings emir of Ninewah, Isa ibn al-Shaybani. We were informed of your location by our most courageous clients through the land of the righteous amongst the land, thus we took it upon ourselves to send a letter unto you before you arrived in al-Hulwan. We expect that our gesture will be met with likewise warmth.
As you most surely know, our armies have decimated al-Hulwan for their transgressions against the downtrodden and for being emissaries of the transgressors (Abbasid). We, with pleasure, inform you that our jihad is most just and is within the parameters of Fiqh. To fight those to whom have become apostates and forsook the rule of Allah is incumbent upon all Muslim and we, the joyous of Allah have taken the difficult and rewarding task of implementing the rule of Allah upon earth and executing the apostate.
The Abbasid have wronged the people and overstepped their rule and thus have become Kuffar and apostate. By Allah, it is the duty of we, and you to cut down such imposters. Thus we, within the providence of Allah, give you a choice:
Join the Jihad and join the righteous or be among the apostate. Muhammad (SAW) said that 'amongst my Ummah shall be 72 sects but amongst them only one shall be in paradise,' let us ask you, to which do you belong? As you are, you are still Muslim, but to remain amongst the imposters will incur our total wrath and from thence will be a Kuffar and will be slain anywhere you turn. Yet, we, assume that you will remain a Muslim from amongst the righteous and renounce being a tool for the hypocrites.
Blessed be Allah, to whom rule is His. Allah is the lone arbitrator, any other is denounced to hellfire. Our brother, Yahya ibn Umar spread his message and was murdered, the blood stains the court of Baghdad and the sword of the righteous yearns to cut. Let Allah decide between those who truly battle and those who tarry, be cursed he who ignores the call to arms, we will cut him down into the depths of the abyss. May the one who doubts be condemned forever with blisters and torture forever more. Ameen."
As Kamal finished, Isa al-Shaybani pulls his sword out and places it on the ground, saying:
"Never have I been a coward. These men claim to resist the Amir, but let him know that his true enemy is not Baghdad but I! Better the gates open releasing hell and Shaytan, than face me! I will tear these imbeciles apart myself, mark this, by Allah they will be turned into rubble before my feet. My anger will not wait for an emissary, let the letter be my sword, no words, let war be the test of Allah, as they say."
Thus began the formal war of the Kharijite rebellion of the north, as Isa al-Shaybani sets out to hunt the Khawarij.
I hope this was a good update, I am trying to take it slowly.