I think it's a more symbolic metaphor. Wolves are vicious pack animals, but when people think of lions, the common image is the male lion being fierce and regal, not the group of lionesses that do much of the actual.
Wolf and panther would be a good one, since Custodes are like James Bond x Bruce Lee + Space Marines. >>30178335
And he took a bullet for the Emperor when they were storming Horus's bunker on Terra, according to the myth. But we know Horus didn't even go down to Terra during the siege, and the Emperor only brought Custodes and Astartes onto the Vengeful Spirit.>>30179996
Before the new GK codex, there was actually a difference between psykers and sorcerers.>>30197739
Considering the dumb knife-ear can't tell that Fulgrim's sword is a shard of his archenemy, that's the only way it makes sense.