I:R - Slaves are only moved to capital. 100% die after revolt.

[GAGA Extrem]

Hello!

Your description does not specify how you dealt with the slave revolt.
Slave revolts should give you the option to negotiate with the slaves (or pardon them). This should resettle most of the slave army.

 

[GAGA Extrem]

There should be a popup after the battle that let's you decide the fate of the slaves.
In addition, during a slave revolt there should be a "Negotiate with the slaves" decision in the decision tab.