The only other card that approaches this level of oppression/aggravation is Dosan the Falling Leaf from Champions of Kamigawa, and this card is way stronger and even more annoying than that legendary creature
Ragavan is simply one of the best cards in Modern at the moment, and has plenty of decisions just because of the dash ability, nevermind whether or not you want to cast a spell from your hand or one from the top of your opponents library
Or even more gutting, simply not being able to take than Ugin
Whether they supply blockers for Blinkmoth Nexus and Etched Champion, pressure to attack an opposing Liliana of the Veil, or simply Shocks on a stick to trade with various Humans, Elves, Merfolk, or Flickerwisps, Pia and Kiran put in the work you need in your Jeskai, Jund, and Grixis decks
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