When your opponent's build step starts, attach this Trait to one of your units.
Equipped unit gets the Imperial subtype and "Pay 0 Force Ambush X+1, where X is the number of Imperial your opponent has in this arena."
Keywords
Ambush
Ambush X: A layered, activated ability that means, "If your opponent deploys, moves, or puts a unit into this arena, this unit does X dice of damage to that unit." Each Ambush can be used once per instance of a unit being deployed, moved, or put.
Equip
Equip: A selective effect on Equipment activated during the build step that means, "Attach this Equipment to a unit. Play only during your build step." You can pay the Equip cost only once per turn.