Nex, General of Zaros

Flying, vigilance
When Nex enters play or attacks, exile the
bottom card of each players library face down.
For as long as those cards remain exiled, you may
look at them, you may cast permanent spells from
among them, and you may spend mana as though
it were mana of any color to cast those spells.
{2}{u/b}{u/b}, {t}: Fateseal 1, then Scry 1.
{x}{x}, {t}: Put up to X lands exiled with Nex
onto the battlefield under your control.