Nibelheim Aflame

Use the power of the target creature as Nibelheim Aflame resolves to determine how much damage it deals to each other creature.

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

If the target creature is an illegal target as Nibelheim Aflame tries to resolve, it won't resolve and none of its effects will happen. No damage will be dealt, and you won't discard and draw even if you cast Nibelheim Aflame from a graveyard.

You can cast a spell using flashback even if it was somehow put into your graveyard without having been cast.

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.