Alduin, World-Eater

Flying, trample

Devourer of Time-At the beginning of your upkeep,
each opponent exiles the top card of their library.
You may cast one of those cards until the end of
turn, and you may spend mana as though it were
mana of any color to cast that spell.

End of All Things -Whenever a Dragon you control
dies, each opponent loses life equal to its power, and
you gain that much life.