영겁의 메아리

19/03/21

A spell cast using flashback will always be exiled afterward, whether it resolves, is countered, or leaves the stack in some other way.

19/03/21

If a card with flashback is put into your graveyard during your turn, you can cast it if it’s legal to do so before any other player can take any actions.

19/03/21

You must still follow any timing restrictions and permissions, including those based on the card’s type. For instance, you can cast a sorcery using flashback only when you could normally cast a sorcery.

14/06/19

Echo of Eons won’t be put into your graveyard until after it’s finished resolving, which means it won’t be shuffled into your library as part of its own effect.