>>96316028
>they have knives that can slice a knight in medieval armor cleanly in half in a single swing.
>No they don't.

Combat Knives are stated as having a monomelecular edge and being constructed from Hypersteel. Gameplay wise, they have a strength of 4 which is the same toughness that Marines themselves possess. In stories they have been used to cut through vehicle plating, a dude in regular plate armor would get destroyed.