The Rune Guide contains the names of the four Realms and their respective rune symbols, and hence alleviates the journey through the Tower. It is to be found in Memory's Garden, the Mansion's central courtyard with the various whispering statues and skeletons hanging from the trees; more specifically, the scroll is kept in the small outhouse accessible in this particular area of the house, by using the small rusty key which lies at the bottom of one of the octagonal water basins.
The rune guide is actually protected by a ward which as soon as Adam lays his hand upon will explode and prompt several Yielders to appear outside in the courtyard. This specific can also be found on the tower gate in Memory's Garden.
You inside. The one who is named Adam. There is no place to run. Come without. Come now. So be it! We shall come to you, one called Adam. Prepare your soul. Now the masks will be mine. The Gnarl has been distant for too long. Prepare to die.