On the front side, Valki, God of Lies is a disruptive early play for black decks that can shape-shift later in the game
To triple a creature's power, that creature gets +X/+Y, where X is twice that creature's power and Y is twice that creature's toughness when Tifa's Limit Break resolves
A half-decent body, some cards into your graveyard, and 3 extra life just to be safe
As an example, let's imagine a player has one copy of , , , and the Starting next week, however, that same player could use four copies of Opt from any of those setsthey could even mix and match the different printings
Thats a downside
Of course, all this power comes with some caveats