If I have control of 2 Battlefields with 1 creature each and an Elder Dragon enters from my opponent targeting both, if I then flash them both back to base are both my creatures alive or does my opponent get to do damage at the new location?
Both of your creatures will survive, and the Elder Dragon's ability will fail to deal damage to them.
According to RiftJudge FAQ #9919 and the accompanying Rules FAQ Clarification (2026-04-29), the Elder Dragon’s "When you play me" ability has specific targeting restrictions: it allows its controller to choose up to one enemy unit at each board location.
When you use Flash in reaction to the Elder Dragon's play effect to move your creatures from the battlefields to your base, the following happens:
- Flash resolves first: Your creatures are moved to your base.
- Elder Dragon's ability resolves: When the ability attempts to resolve, it checks the location of the targeted units. Because the units are no longer at the battlefields where they were originally targeted, they no longer fulfill the targeting restriction of the ability.
As stated in the official clarification: "If you play Flash in reaction to the play effect of Elder Dragon, any units that are moved to a location other than the one where they were targeted will no longer fulfill the targeting restriction of the Elder Dragon play effect and will be unaffected by the ability as it resolves."
Consequently, your creatures remain safely in your base and do not take any damage.