Honestly it's crazy how parallel to Death Knights it is. Death Knights have the hunger, that pushes them to inflict pain or else they themselves will be in pain. With Undead Paladins, the power they wield causes them pain to use. But they use it none-the-less, and endure.
The coolest thing about Forsaken Paladins is that the light literally brings them so much pain and they channel it regardless. It's literally divine willpower that refuses to bow down. These Paladins are literally tasting life that's rotten, feeling a pain so intense it's almost like dying.
And they channel the light anyways. Shits fucking metal.