Just after the library roof smash, head down to the room with the two knights, go out the door to the right, go right and through each room right to the back of the area You can scoop up the Murky Longstaff in the Dreg Heap.Walk up some stairs and hope over the other side, watching for the enemy perched on the ceiling above it. Grab the Murky Hand Scythe in the library whose roof you smash through near the beginning of the Dreg Heap.Drop down to the castle ramparts, deal with the ghostly specters, head left up the stairs, go up again, and it's on the ground right at the top. The Aquamarine Dagger is located in the first area, the Dreg Heap.Dark Souls 3: Ringed City weapon locations
If you need specific walkthroughs of each area, then consult our main Dark Souls 3: Ringed City walkthrough and guide. There are a few new weapons, armour sets, and spells to be picked up in the Ringed City of Dark Souls 3's final DLC, so if you're coming up short here's a handy list of what's what and where to find it.