Permanently enchant a melee weapon to often heal for 75 to 125 and increase Strength by 100 for 15 seconds. At level 70, Crusader heals for 45-75 health and gives +60 Strength.
Scarlet Archmages in the cathedral in Tyr's Hand in the Eastern Plaguelands, respectively, with a drop rate of approximately 0.5%. Prior to the Burning Crusade expansion this formula was heavily farmed. Crusader is now one of the best enchants for heirloom weapons as it can be applied to a level one item.
A weapon enchanted with Crusader glows bright white. Crusader procs an average of 1ppm (procs per minute).
% to Proc = Weapon Speed * 1.667
At low levels (e.g. level 9) Crusader procs very rarely. Its not known at what level the standard proc rate takes effect.