Darrien, Chosen of Aclazotz

First Strike
{2}{b}{b}{t}: target opponent loses X life, where X is your devotion to black. Put X +1/+1 counters on Darrien.
{b}{b}{t}, sacrifice Darrien: search your library for a card named Aclazotz, Lord of Darkness, and put it onto the battlefield. Activate this ability only if there are 10 or more +1/+1 counters on Darrien and if your devotion to black is 5 or more.