There's still a question that remains unanswered: how does the Seed work? In other words, what did Solar Flare do to end the curse? Also I'm curious why the bat pony Oracle needs it, and how to find the missing pieces.

While you still have the chance, you decide to ask Ratatosk about the Yggdrasil seed.

Ratatosk: "You mean to tell me that after everything you went through to get it, you don't even know what it's for? Oh, the absurdity of mortals!

… Well, I suppose there's no harm in telling you what it is, at least. It's your responsibility now, after all.

Despite its name, the Yggdrasil seed isn't some kind of tree seed. Now, don't give me that look, it's true! What, did you think you could just plant it in the ground and sprout another Yggdrasil tree? No, none of that!

Think of it as… one of your enchanted gemstones! Sort of. It's a crystal with magic inside of it, ready to be tapped. And there's an abundance of it in there, too! Enough magic to restore the life of, say, a giant world tree that just happened to burn down, for example. You get the idea.

But there's a catch! Indeed, while you hold the seed's coat in your hooves, it's merely a window to what's inside of it, which actually lies far beyond the firmament. In other words, when tapped into, any arcane channeled through it will be lost to the aether!"

Not unlike the sun and the moon, you recall from an earlier history lesson. Taking another look at the Yggdrasil seed, you wonder how Solar Flare managed to restore an artifact seemingly so powerful all on his own.

Ratatosk: "Oh, that's just magic one-oh-one. If any creatures in this realm can figure it out, it's you little ponies! The same creatures who created the Philosopher's Stone to begin with.

And that's all you'll get out of me today, I'm afraid! As the sole courier of Yggdrasil, I have great and important duties to attend to. It has been a pleasure, heroes! I wish you the best of luck in your next endeavors!"

Your party thanks the giant squirrel, and bids him farewell, before he spirals up the trunk, and disappears into the giant ash tree's distant foliage above.

Your gaze then returns to the Yggdrasil seed. The more you learn, the more questions you have about it, one of which you speak aloud; what need does the Oracle have with such a legendary artifact, anyway?

Moonflower: "Ooh, good question! I dunno. I never really thought about it."

You let the bat pony take a closer look at the seed. Beneath its glassy surface, sedentary stars glow warmly in a perpetual night sky of its own.

Moonflower: "But I think this is the one she wanted us to get. So now, we just gotta bring it back home!"

Apple Basket: "And hopefully not run into any more pirates on the way there."