When Valki enters, each opponent reveals their hand. For each opponent, exile a creature card they revealed this way until Valki leaves the battlefield.
: Choose a creature card exiled with Valki with mana value X. Valki becomes a copy of that card.
As Tibalt enters, you get an emblem with "You may play cards exiled with Tibalt, Cosmic Impostor, and you may spend mana as though it were mana of any color to cast those spells."
Cast Valki early as a disruptive 2-drop that strips opponents' creatures, then ramp hard into the seven-mana back half, Tibalt, Cosmic Impostor, who grinds the board into oblivion while you play off the top of everyone's library. You win by accumulating overwhelming card advantage and resource denial, eventually closing with Tibalt's loyalty pressure or a big payoff cast from exile.
Two-for-one flexibility: a cheap creature that doubles as a backbreaking planeswalker bomb
Tibalt's ultimate exiles all graveyards, hosing reanimator and aristocrats decks
+2 generates relentless card advantage by playing off the top of every library
-3 is repeatable spot removal that exiles, dodging recursion
Hard to deal with permanently—both halves demand separate answers
Tibalt costs seven mana and is slow without heavy ramp
Valki's body is fragile and the exile is undone if he leaves the battlefield
No protection built in—both halves are easily removed before they generate value
Color identity locks you out of green ramp and blue interaction
Top-deck play from +2 can be inconsistent and unpredictable
Synergizes with playing cards off the top, accelerating your engine like Tibalt's +2.
Add fast mana and ramp—Mana Crypt, Jeweled Lotus, Dockside Extortionist, and the Coffers/Nykthos package—to cheat Tibalt out turns ahead of curve. Include The Chain Veil and proliferate effects to chain loyalty activations, plus tutors like Demonic Tutor and Vampiric Tutor for consistency. Round out with strong BR interaction and a few high-impact bombs to play off Tibalt's emblem.
Legendary Creature — God // Legendary Planeswalker — Tibalt
: Choose a creature card exiled with Valki with mana value X. Valki becomes a copy of that card.