Pride Sovereign

Exert was built around a single question: what is a creature's untap step worth, and what would you pay to spend it a turn early? Most cards in the mechanic answer with a one-time stat swell or an extra swing of damage. This one answers with a token engine. The white-pip activation spits out two lifelinking Cats, and because those tokens are Cats, each pair feeds directly back into the +1/+1-per-other-Cat clause that governs this creature's size. Note the direction of the loop: the body only counts other Cats, so it grows off the board around it rather than off itself. Every exert widens that pool, and a wider pool means a bigger body in both power and toughness, not just a taller wall. That is why it cares about Cats specifically rather than tokens generally; the payoff is written to reward exactly the fodder its own ability produces. The split color identity is what pays for the engine: the body and the tribal counting are green, but the token spigot demands white, so you cannot run it as a mono-green payoff and you cannot lean on white while ignoring green. The result is a tribal centerpiece that has to earn its tribe in two directions at once, inflating its own stat line while stockpiling the Cats that make the next exert worth the tempo of a skipped untap.