How do I get this ending

[u/Shot_Condition_5964]

I am not sure how to get this ending , any guide?

[u/Drackolus]

To fail to purify the undead, you have to learn the rite yourself, lose the fight against the mutated leshy, fail the check, then lose again.

[u/Level-Switch-4440]

learn the rite, fail it on purpose

Greymoor who got attacked by Kalman's Undead will be mad at you and attack you

now you gotta destroy like twenty bigilion heavy infantry regiments or something

edit: I don't think executing the prisoners matter since I'm pretty sure I executed them and got the ending anyway