The mighty charger serves as the steed for all those who serve the Light.TCGWG 51A human and blood elf paladin on their chargers, showing the differences side-by-side.
The Charger is an epic version of the Warhorse mount only available to paladins. It is trainable at level 40 and up until Patch 4.0.1 was a reward for completing a lengthy quest series. Completing the lengthy chain awarded a Feat of Strength achievement and also rewarded Journeyman Riding. Training this ability at level 40 requires 150 riding skill and the Warhorse ability learned.
Blood elf paladins receive a different but similar ability, [Summon Thalassian Charger], by the same means. Humans and dwarves receive a [Charger] with blue livery and golden-plated armor, and which exudes a light golden aura. However, the blood elf Charger has red livery, with what appears to be brass armor, and exudes a reddish aura.