yes this is a necro but people here say that it would be bad if an allied army just stood and watched you fight an enemy they aren't in a war against with you.
let's immerse ourselves in the situation
For the sake of immersion let's ignore that you are a jew and thus also a different religion guy. Especcialy since back in those days jews and christians in that area where living together and probably tolerated each other more so with the muslims expanding.
you are the king of abyssinia, you claim to be descended from salomon and rightful ruler of the entire area
I am the ?duke? of alodia your neighbour I am constantly in your shadow fearing that you grow strong enough to demand me to bend the knee at swordpoint
This is medieval europe (at least the game mechanics are supposed to imitate it, and so we get feudal africa) where the death of a king is reason enough to march on his lands and claim a few duchies (or maybe more) because reasons.
you are at war with a duke like me, your armies are crushed, good, I can now invade your land and take half the cake for myself.
suddenly your lands are assailed by heathens, demonspawn. Wait I'm sorry "YOUR" lands? You cannot defend your peole from a mere infidel and you call yourself a king of these lands? No I'm taking them but I don't want a burning pile of ash to rule over.
So I go beat the infidels (plus the priests were pestering me all day to save our brothers in faith so maybe now they will go quiet). we march together like bff's and beat them to a pulp .
suddenly your army is attacked by the same duke you were at war with before those infidel shenanigans.
Do you think I will help you? Do you think I have any reason to help you?(as said above we ignore the christian vs jew problem)
Maybe . Maybe I will. but first I hear out the propositions of both sides and hear what they can offer.
So what can offer me the king of abyssinia who is on the verge of losing his throne? And can his offer beat the one that the duke of axum, who seeks to take the throne of abyssinia for himself, has for me?