Your prisoner does not know precisely what magic items his rival has in his possession.
Alright then. He has the dagger for sure. He's now the number one priority for us. Bonus points if we take him alive for sacrifice.
@Duesal , might as well bring the full list of things we need dead? We need to kickstart the Inquisition.
Funnily enough, the List is remarkably short when it comes to things we want dead that we can actually act against.
Red Abishai whose scale we have -- sure, we can go after it, but it seems to have anti-divination measures
Tiamat Clerics -- on the other side of the Bone Mountains, and they do divination randomly twice per day
Red Dragon Wyrmlings -- all four of them have permanent Mind Blank, but we know the location of one of them... and it has the same protections as the clerics
The Blackfyre -- he's pretty well hidden from us, not sure how well an attempted scrying would go
The Lannisters (Gerion & Lanna) -- we know exactly where they are, and we could get them even without scrying, but killing them will make Tywin do stupid things
Robert -- same as the Lannisters, we can't go after him
Deep Ones -- all protected by a faction-wide Mind Blank, and further protected by the ceasefire
Potential Beholder in Plane of Earth -- we can scry it (just imagine the trophy), but it does regular divination which is how it escaped us the first time
The Efreeti -- specifically that one noble who we sold the Devil's Eye to, we can hunt him down, capture him as a sacrifice, rob him while we're at it, and get the devil's eye as a sacrifice as well, and we can also get the Bey of Beggars and go after Efreeti Whaling Ships
The Others -- we need to figure out who their agents South of the Wall are the old-fashioned way, and anyone scried Beyond the Wall can't be teleported to anyway
Daemons -- any cultists and daemons we know of will be hunted down and annihilated
Demons -- same as above
Devils -- that fucking Contract Devil
The Seven -- scry-and-die problematic champions, sacrifice them to the Old Gods, seize artifacts sacred to them and sacrifice those as well
Other than that... pretty quiet overall. The List used to be a hell of a lot longer.