Sinister Strength

Most auras that pump a creature do exactly that and nothing else; the second clause here is the part that earns its slot. Making the enchanted creature black is a color-fixing rider grafted onto a stat boost, and it exists to feed the color-matters machinery this kind of design was built around: cards that punish or reward black creatures, fear that wants the attacker black, and the dual-color tensions of the era. The +3/+1 is a brawler's split, weighted toward offense in a way that turns a midsize body into a clock while doing little to protect it, since the single point of toughness rarely lifts it out of the removal ranges it already lived in. That asymmetry is deliberate: this is a beatdown enabler, not a way to protect an investment. The color-changing line does quiet defensive work on the right board, slipping a creature out from under black's own "destroy nonblack creature" effects (the Terror family) that demand a target that is anything but black. Structurally it sits in the long line of cheap black auras that trade card economy for tempo, the same bargain Unholy Strength struck earlier with a smaller bump and the same demonic flavor of borrowed power. What sets this one apart is that it is not just paying for stats; it is paying for stats and a color, and that second half of the bill was always the point.