Justice may be blind, but Lavinia is always watching.

Each opponent can't cast noncreature spells with mana value greater than the number of lands that player controls.
Whenever an opponent casts a spell, if no mana was spent to cast it, counter that spell.

Lavinia, Azorius Renegade

Secret Lair Drop

"I told Jace that Ravnica would fall apart if he didn't take his responsibilities seriously. I didn't want to be right."