Why is Sigmar's "I am the Hammer?" listed as 'Basic' in the traits?

It's an NPC action. The red side says "Used By: Magnus Gottschalk", and there's some NPC-only mechanics (A/C/E) mentioned on the card.

NPCs frequently have abnormal "basic" actions. Why exactly is never really explained, but my personal theory is that at some point in the design process, NPCs weren't going to have access to the normal basic actions. (In that theoretical model, NPC's only Active Defenses would have been defensive A/C/E spends.)

there are a few cards like that one that caught me off guard. I couldn't figure out what in the hell it was intended for and then flipped it over to find the named NPC on one side. Eduardo Rodriguez has a few cards like that as well.

Basic might imply that these are actions that this NPC allways have and is not counted towards the amount of action cards suggested on the npc cards.