Opening themselves up to the full power of the darkness, darkwalkers cared little for the fate of their own souls, which others might try and protect from the corrupting powers that darkwalkers dealt with on a regular basis. Darkwalkers knew, however, that this ultimately limited their power and so did not give in to such fears, accepting what came as a matter of consequence.
Most warlocks who dealt with the demons of the Abyss were more than a little concerned with losing their souls in the process, a danger far from insubstantial or imaginary. However, darkwalkers felt that protecting oneself from this was merely delaying the inevitable so instead of squalling in fear or trying to hold back their power, darkwalkers embraced it fully, using it to confront and counter the powers they dealt with rather than falling back from them. As a result, darkwalkers obtained an almost otherworldly presence, removing themselves from the affairs of the mortal world while not wholly embracing the ways of their dark patrons. Gradually, they moved closer into the other world's perspective but it was a slow process and one which darkwalkers were willing to endure.
As part of their method for maintaining independence from those who would control them, dark warlocks used their very souls as a bargaining chip. When they desired something, they gambled with it, throwing it in as a part of their side of a bargain, for which they gained unimaginable power in exchange. This process meant that, gradually, darkwalkers began to lose the traits that set them apart from such demonic forces and the body that housed their soul became nothing more than a temporary home on lease. Eventually, unless a darkwalker found a way to counteract the power of their patrons completely, they would lose their soul completely, becoming a corrupted pawn of darkness.
Darkwalkers, as a result of the dealings they forged, began to transcend the Prime Material Plane itself. Darkwalkers who had only just begun to take on their career might exhibit greater strength and power when they were insubstantial and partially absent from the plane. In this form, darkwalkers were deadlier, dealing more lethal attacks dependent on their intellect. Similarly, creatures that were already insubstantial lost their protection against attacks from a darkwalker, who could hit them as easily as if they were solid. It was also easier for darkwalkers to slip into this form.
The invocations of a darkwalker similarly enhanced the darkwalker's ability to phase partially out of the Prime and into another plane, putting them in a place somewhere in-between. Fading spiral, for instance, allowed a darkwalker to use the power from their darkspiral aura boon to become insubstantial. Similarly, wraithform blast, in addition to dealing deadly necrotic power to a darkwalker's enemy, caused the caster to become insubstantial.