Quick question because I don’t know - why are there Hell Knights in Magnimar? What order are they - as some have very different areas of focus?
They are incredibly strictly Lawful - if they don’t have specific jurisdiction then I don’t think they will do anything ?
Also it sounds like they have just dragged a high ranking judge to the knights, told some outrageous stories and blamed it all on him. And to the best I can tell offered no proof beyond their word
Just because they can discern lies it doesn’t mean they have to believe what the group say. People can resist that ability if strong willed or work their way around it if clever or tricky. I visit to the mill by the knights would reveal that the PCs aren’t being completely honest
If anything the hell knights would also attempt to apprehend the PCs because their only evidence seems to point to an assault on a judge. You could even say ironbriar is smart enough to have rumours out the sczarni are after him to make it look like an attempted gang land hit and the PCs are hired goons
Powerful corrupt individuals in high ranking positions are not taken down by the word of a few strangers (play up that aspect as well) with no proof - in fantasy worlds or real worlds
@Wibs I have few questions myself.
Did the PCs (1) actualy commited a murder, or just (2) created a fake murder scene? Or did they (3) lure Ironbriar in a trap and stopped him before he commited any murder?
The Hellknights will definitely try to take Ironbriar in their custody. They would also try to take the PCs as well for questioning. If the PCs resist, the Hellknights may use force.
(1) By questioning Ironbriar the Hellknights may be able to tell that he's innocent of the crime he's being framed for. If the party haven't presented any evidence of Ironbriar's other crimes, the Hellknights may let him go - he's an important part of the Magnimar's legal system, and holding him in custody doesn't seem to help upholding the law. The PCs are now accused for murder. They need to escape and prove Ironbriar's crimes. If they do that, they may be spared the wost punishment for the murder, which will allow to continue the campaign.
(2) As in (1), but the PCs just need to answer for trying to frame a city official. The city may get them fined (though Hellknights would probably prefer some corporal punishment), but if they eventually prove that Ironbriar is really a criminal, they get a return (no apology from Hellknights).
(3) With no additional evidence against him, and no crime actually comitted, Ironbriar may be able to weasel out of this, and let go. But if the evidence (like the cultist masks and weapons) is enough for the Hellknights to keep Ironbriar imprisoned, the Hellknights would continue the investigation, and find additional evidence in the sawmill. They may decide to attack the clock tower. The PCs may be asked (or forced) to assist.
@Lamathar The Hellknights in Magnimar are a small detachment from the Order of the Nail. They have an oputpost in Naos called Bastion of the Nail. Their presence in Magnimar is to show they won't ally with Korvosa aganist Magnimar.
They are Lawful, but the follow their own Law, which they believe superior to any local laws. They would arrest an official of a goverment, if they consider him criminal. However, if they won't be able to gather evidence against him quickly, they may end up being pressured into releasing him. Because of that, if all the evicdence is testimony, they may hold off and perform additional investigation before arresting an important person.
Few questions: How much do the PCs know of Xanesha, and how much of it did they tell Hellknights? What Acacia knows about the PCs and their investigation? Also it seems that they do not know that it was Foxglove killing in Sandpoint, how is that so?
If Ironbriar just denies everything, the PCs really don't have anything that would make the officials to arrest Ironbriar. The PCs may claim that he was present in the sawmill and was leading the cultists, but they don't really have a proof. Moreover, Ironbriar ahs agood reputation in upholding the law as a Justice, so Hellknights would be prone to side with him. Unless the Hellknights manage to detect that Ironbriar is lying, they will insist on letting him go. If they do detect the lies, they could detain him, but they would require more evidence to justify this before the City Council. Either way, they'd arrest the PCs (just in case) but also assure them they are going to check their story and investigate the sawmill. They may find the ledger, but since it is encrypted, they won't be able to present sufficient evidence immediately, and Ironbriar will be released.
Consider however, that the Hellknights may also be able to detect that Ironbriar is under an enchantment spell (DC 25 Sense Motive or detect magic and DC 19 Knowledge (arcana) check recognizes enchantment). If Ironbriar is released from the charm monster that Xanesha put on him, he'd turn against her. He wouldn't tell anything to Hellknights, because then he'd need to admit to his crimes, but he may contact the PCs afterwards and offer an alliance: if they drop all the accusations against him, he'll tell them about Xanesha.
The Hellknights would still eventually decode the ledger (which may become a source of information if the PCs refuse Ironbriar's offer), so Ironbriar would have to either somehow use his influence to recover the ledger or run from the city before that happens - choose whatever fits your story better.
Is there any way to "see the past" that could 100% reconstruct what happened? A spell of some kind?
There is no such spell that woul be reliable, as such a spell would be a bane of every mystery adventure ever. The closest one is commune that may be used to ask a deity several yes/no questions, but even deities are not omniscient. The local head priest of Abadar is high enough level to cast this spell, and law is one of Abadar's areas of concern, so he could declare the PCs innocent and confirm their story... or reveal that they are not telling the whole truth. Since one of the Justices is accused, he may deem the case to be important enough to get involved and ask for a divine judgment.
I believe that once the Hellknights start investigating the sawmill, they'd interrogate all of the workers, possibly discovering hidden cultists; one of them may break and corroobrate the PCs' story.
Once the items belonging to the murder victims will be found, one thing will become clear: the PCs know who the murderes are. Since the murders were happening for some time before the PCs arrived in town, it's impossible for them to be murderers themselves, which gives some credibility to their accusations. They still may be suspected to work with the murderers, so that's not enough to convict Ironbriar, but it may be sufficient for him to be under suspicion. And once the ledger will be decoded, it will be proof enough.
Regarding the charm spell on Ironbriar, remember that it may also expire on its own. If ironbriar finds himself in a position that he won't be able to visit Xanesha for several days, the spell may expire and he can figure out on his own that he was charmed.