When we last see Beric Dondarrion, he's trying to convince the Hound to join the fight against the White Walkers. And here's the thing: it looks like he succeeds. We know Beric is fighting alongside Jon Snow. You can see his flaming sword in the wide shot we included above.
That said, is there a greater role for Beric to play? If you know the prophecy of Azor Ahai, then you're aware of the mythical sword called the Lightbringer. And, well, a flaming sword imbued with magic seems like just the thing you'd call the "Lightbringer." Beric himself couldn't possibly be Azor Ahai reborn. After all, he's one of the worst fighters in Westeros and has died (and been resurrected by Thoros of Myr) six times. The most popular theory is that Jon Snow is Azor Ahai, and that's what makes Beric's new position pretty interesting. Maybe his sword will fall into Jon Snow's hands, and Jon Snow will fulfill the prophecy.
