The Witcher 2: Assassins of Kings

Addan Deith can be looted from a chest in the northwestern rune room during the quest The Gargoyle Contract in Loc Muinne during Chapter III.

After obtaining the weapon, Geralt starts reading a message from its previous owner:

You hold the sword of Aramil, who defied his king's rule. The Lord of the Wild Hunt desires the gene of the Elder Blood. He seeks to fling open the gates between the worlds, so that terror and destruction may reign.
The King of the Hunt ordered me slain, and the wraiths born of his command assumed living form, pursuing me through the voids between the worlds for centuries.
I have arrived at Loc Muinne. Though tired, I know I will not rest. The riders of the Hunt draw near. On my back I can feel their deathly breath.

The Witcher 3: Wild Hunt

This sword can be obtained in a number of ways:

Associated Quest

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