Knights of the Silver Hand
In Warcraft II, clerics were replaced with paladins, an upgrade for knights that gave them the ability to cast spells similar to what the clerics had. Now, in the manual for the second game, it was explained that the clerics had suffered heavy losses during the First War (the first game), due to their lack of martial training and that two figures - Uther Lightbringer and Archbishop Alonsus Faol - came up with the idea to create an order that would meld the dual roles of warrior and cleric into one, thus the Knights of the Silver Hand was born. I like how Blizzard actually took the time to give an explanation for the clerics replacement in Warcraft II, it really does give the games more depth.
Edit: Did some picture swapping.