Velris, Weaver of Futures

Whenever an opponent draws a card, exile the top card of their library.
You may cast cards exiled this way for {3} less, and you may spend mana as though it were mana of any color to cast them.
{1}{u}{b}{r}, {t}: Exile the top two cards of each opponent's library. Until end of turn, you may cast one of the exiled cards without paying its mana cost.
"All threads lead to me, and I decide which are severed."