Changeling Sentinel

Vigilance is the wrinkle that separates this Shapeshifter from the rest of the family: the keyword that lets it press an aggressive board without surrendering the home front. The changeling line gives it a universal type line, so it counts toward Goblins, Elves, Soldiers, Merfolk, and any other tribe a deck wants to muster, and it sits inside the buff range of every lord that reads "other creatures of type X get +1/+1." Those buffs are static, applying the moment the Sentinel hits the battlefield, which is exactly why a body that answers to every tribe is so valuable in a tribal shell: it picks up every continuous bonus the board is offering simultaneously. The price is the rate. Four mana for a 3/2 is plain by white's standards, and that is the recurring bargain across the changeling cycle, where the value lives in the type line rather than the numbers. This one earns the extra mana by keeping itself useful after the attack step. The vigilance means each swing leaves a defender behind, so a board flooded with these bodies can race and hold the ground on the same turn, which is the trick a vanilla-statted changeling never manages: it attacks, then stays home, then attacks again.