Right it was rather good but the end was the most interesting it seems mannfred is gathering an army and planning to go back to the realm of shyish(he said the power of his army will be felt in the realm of the dead) to retrieve Tarsus/Tarsim. Now he says he wants to make him his prisoner but I don't think it's as simple as that(I suspect it's a rescue) I mean through out the audio drama series he held Tarsim in high regard even when he was mortal. Maybe his last words had that much effect on him? Perhaps vlad's words from end times also affected him? Well Ramus did not know they had a past relationship and that he tried to save Tarsim during the nagash event, well he was being crushed alive by nagash so he was not in the position to look around.
They also talk about how Tarsim's situation is unprecedented and the amount of shame surrounding it for the hallowed knights. All through out the novels the common thing is that many storm cast don't fear chaos many spat in the face of that but many of them do fear death and the effects of it. They even note in another novel many who came back from meeting nagash their souls were too sundered to be reforged. I suspect that nagash has most likely twisted Tarsim into something of death it just seems to be leaning towards that. I think sigmar does not percieve one of his own stormcast falling to chaos but falling to nagash? That may happen and it may surprise him plus the fact that helstone had a profound effect on Tarsim even if he did not really show it.
I also suspect that Nagash is going to use Tarsim to make mannfred bend the knee since he is the only friend/ally he ever had or if he has been changed he will convince nagash to show mercy and let him back in the club.