"It is now confirmed with absolute certainty that Dark Templars' Warp Blades react to the user's strength of will. Perhaps, given some time, we can use such information to our advantage should we have any further encounters with Dark Templar."
The origins of the warp blade lie on the xel'naga ship the Nerazim departed Aiur in. Gaining access to new knowledge, the Nerazim used the psi-blade as a template to forge an instrument with which to shape their burgeoning psionic ability, and infuse it with Void energy. Warp blades are more powerful than psi-blades, and react to the user's strength of will, turning centuries of discipline and training into a powerful weapon. Further iterations on its design yielded scythe-like blades, which helped diversify the combat style of the Dark Templar. These shadow scythes are wielded by the Zer'atai and MatriarchVorazun, while the Lenassa favor "wickedly curved" warp blades. By comparison, the centurions of the Nerazim Shadow Guard have their warp blades mounted on forearms, similar to psionic blades of Khalaizealots.
Warp blades are able to parry psi-blades, and be parried in turn. After the severing of his nerve cords, HierarchArtanis demonstrated the ability to wield a warp and psi blade in tandem. According to the Daelaam archives, PraetorFenix was able to wield warp blades when he used them to slay Nerazim terrorists who had taken over a Conclave tower.
Like psionic blades, warp blades also vary in color. While those of the Nerazim are green, those of the centurion shadow guards have a light blue color.