The Proscriptions of 43 BC

(You may cast a legendary sorcery only if you control a legendary creature or planeswalker.)
Choose three target creatures, then target
opponent chooses up to three target creatures.
Destroy all chosen creatures. For each legendary
creature or Noble destroyed this way, create a
colorless Treasure artifact token with "{t},
Sacrifice this artifact: Add one mana of any color
to your mana pool." You become the monarch.