You commit a crime whenever a spell or ability you control targets an opponent, something they control, or a card in their graveyard. Crime decks deliberately perform these already-common game actions while adding permanents that reward you for your villainous behavior.
Intimidation Campaign can repeatedly return to your hand as you commit crimes, while Vadmir, New Blood grows the first time you commit a crime each turn. Removal, discard, and targeted graveyard hate can all advance the strategy while doing jobs the deck already wants done.
