Wildfire Devils

The chosen player chooses which card to exile from their graveyard.

The copy of the card is created in exile and cast from exile, not from a graveyard.

You choose a player at random and they exile a card all while the triggered ability is resolving. No player may take any actions between the two or between exiling the card and you copying and casting it.

You can cast the copy only as the triggered ability resolves. If you don’t want to cast it at that time (or you can’t cast it, perhaps because there are no legal targets available), the copy ceases to exist. You can’t cast it later.

If a spell has {X} in its mana cost, you must choose 0 as the value of X when casting it without paying its mana cost.

If the chosen player has no instant or sorcery cards in their graveyard, Wildfire Devils’s ability does nothing. You don’t pick a different player.