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The Seal

In the Khufu Desert Depths, place Set's Blood on the Right Pyramid Statue and Horus' Feather on the Left Pyramid Statue.
 

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Introduction

Set's Blood and Horus' Feather are ready, and the time has come to go to the Khufu Pyramid. Unfortunately, Milia didn't leave any clue as to how to use these items to undo the seal.
Garlandi still believes you are capable of breaking the seal to get Wraith Tome. But, he is more concerned for your safety than he is the seal.

NPC Dialog

Milia wasn't clear on how we are to use Set's Blood
and Horus' Feather to break the seal. However, I
believe you can do it. I hope you'll be all right. The
Wraith Tome is undeniably evil. Please be careful!