There are 20 Space Marine Legions in Warhammer 40K, with two being unknown. The canon is fluid and dates back to the magazines and books released in the 80’s—so it’s hard to verify when exactly each Legion was first mentioned, but thanks to dedicated fans, we have some idea.
All Space Marine Legions in Warhammer 40K
What’s the difference from one Space Marine Legion to another? A lot, it turns out. Image via Saber Interactive
The Legions, once called Legiones Astartes, were created by the Emperor of Mankind to conquer the galaxy on multiple fronts. They were each led by a Primarch—the genetically engineered children of the Emperor with superhuman abilities far surpassing the Space Marines in their Legion—and each also had a different specialty.