Old Demon King

You can activate Old Demon King activated abilities only if you control a "Lost Izalith".
{b}{b}{r},{t}: Return any number of Chaos Demon creatures from your graveyard to your library,
then shuffle it.
{x}{r},{t}: Return a Chaos Demon with X
converted mana cost from your graveyard to the battlefield.
If Old Demon King would die, it gets -4/-3
instead.