What about creating a new enemy called corrupted knights, who use weapons that we have access to as their gear. That way we get a taste of our own medicine because they'd use our OP weapons on us. Perhaps they could even copy our exact loadout when they spawn (random chance to copy 1 of the loadouts in parties).

You could also have gremlin snatchers as a new gremlin type that uses like acheron and combusters that they stole from the spiral knights.