Zireael and Kelpie: The Sword and the Horse

Head south and east to reveal a morphic projection of the elf you seek. After some deduction, and knowledge that Ciri’s sword is named “Zireael” or “Swallow,” you embark on an inspection of nearby glyphs with a Swallow motif. Now head south, into a pungent, but vast chamber. The yellow vapor is from toxic mushrooms growing here, so set the clouds ablaze (from a distance) using Igni before you encounter and slay all the wraiths guarding this cavern.

Harvest any mushrooms you wish as you continue roughly northwest into a large tunnel with climbable sections. These lead to a strange octagonal chamber, and another elvish projection to listen to (by the Sign of the Swallow).

Carefully inspect the glyphs along the wall, optionally using your Witcher Senses. None of them are signs of a horse, but activating the Kayran Sign triggers a spell that conjures a duplicate of both you and Keira! Return with more potent strikes to see off both of these reasonably weak, cloned specters! That chalk drawing of a dog isn’t much help either; it explodes when touched, dealing significant damage and knocking you back. Leave that alone!

It seems the image of Kelpie isn’t on this higher balcony, so jump and drop down into the octagonal pool. Wade to the picture of the horse and activate it. Then dive and swim roughly westward and northwest to escape the water pit. Climb the steps to a second horse glyph and activate it. Then scramble up the rubble and drop back down into the room; a door rumbles open.

Through the door is a dead-end, and a portal Keira is sure distorted her own attempts at teleportation. It features the Sign of the Swallow; stand next to the arch and activate the portal. Then step inside.

The next chamber features a lurching golem that must be fought. Climb the ruined stairs behind the golem, and turn left (southwest). Head down the passage as it bends around to the south. On the left there is a side passage down to another portal. Ahead and left is a dead-end cave guarded by a gargoyle. The latter isn’t necessary to face, but when you enter there is no going back, since the entrance closes behind you! Awakened, the gargoyle needs to be slain for the stone door to open again. If you don’t feel ready to face the gargoyle, head down the side passage to another identical portal. Activate the Swallow Sign and step through.