Tiamat and the Universe

Dragons you control cost {w}{u}{b}{r}{g} less to cast.
Permanents you don't control cost {3} more to cast.
{t}: Create a 3/3 dragon with flying.
{t}, {2}: Deal 4 damage to a non-player target.
{t}, {1}{w}{u}{b}{r}{g}: Search your library for a card
named Tiamat, Endbringer and put it in your hand.
Activate this ability only if you control 5 dragons.
Tiamat is ancient, older than existence.