Wikia

Classes
Warlock	Mage	Rogue	Death Knight	Warrior
Hunter	Druid	Priest	Shaman	Paladin

Paladin: Defensive supporter/healer with powerful short-term buffs and auras that affect any party members around the Paladin. While criticized for having the lowest DPS of all the classes, they make up for this with sheer toughness. Generally considered the strongest supportive class in the game, the Paladin can sacrifice himself to save the group. Dependant on gear. --WowWiki

Blood Knight: Blood Knights are the horde version of Paladins. Whilst the players assume the title Paladin, they are referred to in game by other Blood Elves more often as Blood Knights than the generic Paladin.