Avacyn, Redeemed by Darkness

Deathtoutch, indestructible, first strike, flying, menace
When Avacyn enters the battlefield, destroy all permanents. (Including lands)
When no light remained in Avacyn's heart, so she felt ... redeemed. She could finally see the world clearly again, with no light dazzling her vision. She had returned to her true home - the eternal night.