"They finally left." After the army departed, a Blood Elf assassin slowly emerged from concealment. He glanced at Orista, who had a gaping hole in his chest, sneered, and picked up the fragments of the Shadow Talisman from the mage's body.
When Patrick learned that these demonic minions could use shadow energy to create a "Divine Shield," his interest was immediately piqued. Divine Shield was a skill exclusive to Paladins. They used the "purification" and "dispel" properties of Holy Light energy to create a shield that repelled all other energy and matter to protect themselves. That was what Divine Shield truly meant.
In a sense, Divine Shield did not make someone "invincible." At the very least, it could be broken if you were powerful enough. Even an avatar of C'Thun could unleash a Death Ray Wall that ignored Divine Shield and directly killed the person under its protection.
Since Holy Light could be used this way, why not shadow? The shadow energy shields used by those three demonic minions in the Blasted Lands had already proved that the idea of a "Shadow Shield" was viable.
As an energy opposed to Holy Light, shadow energy likewise possessed concepts such as "disintegration" and "disintegrate." Setting aside their opposing attributes, purification and dispelling seemed essentially no different from disintegrating and breaking things down. Moreover, purification and dispelling were not exclusive to Holy Light. Elemental power and the force of nature could achieve the same effects. Shamans also had purification skills, and even fel could dispel things. Doomguards likewise possessed dispelling abilities.
In that case, why had no Shadow Knight appeared as a counterpart to the Paladin? Priests who believed in Holy Light could become Paladins directly, so could Warlocks who used shadow change their class to Shadow Knight?
That was the entire purpose