Amani, the Shield-Breaker

Amani, the Shield Breaker enters the battlefield with 2 block counters on it. (Remove a block counter, prevent all damage done to this creature this turn.)
Position 1 or 2 — Wither (Gain this ability if in position on upkeep. Change position during attack step, and only if you do not attack.)
"Shifting, swaying - she mesmerizes her prey before the final strike."
— the Ancestor