This spear is featured as an artifact in Vorador's mansion (in Legacy of Kain: Defiance). It is one of the spears needed to impale the water-spouting Hylden Gargoyles that block the entrance to the water forge.
The Spears the statues hold and which are later used to impale some Hylden statues to allow Raziel access to the Water Forge refer to Raziel in his different 'states' - they are named 'Heart Seeker' (after Raziel's quest as a human to kill Janos) 'Blood Drinker' (vampire) and 'Soul Stealer' (wraith).
An intriguing depiction of the spear lies in the crypt of Vorador's Mansion, where an Ancient winged vampire with a skeletal face, holds the spear in her right hand, and a blue crystal in her left hand. What this means as to the significance of the spear itself is unknown.
In the unlockable pictures from Raziel's tomes, the spear is seen with text that says "blue crystal" and "blue metal".
The Soul Stealer as it initially appears in Defiance