Pravis, the sacred City

{t}: Add {w}
Whenever another non-token human enters the battlefield, if Pravis, the sacred City is untapped,
creat a 1/1 black and white human
creature token.
{x}{b}, sacrifice X creatures: Create an X/X black
demon creature trocken with flying and menace,
where X is the total power of the creatures sacrificed that way.