From behind them, a voice spoke gently, "Now what brings my father here with a Shadow and Valkyre?"
They were shocked. First, they had been discovered. They kept hidden because they did NOT want to influence the world, just protect. Second, the fact the word father was used had implications for Big Mac.
Trixie nervously asked, "Big Mac, is there something you should be telling Cheerilee?"
They turned around to see... "Miss Zecora?" Big Mac was a bit surprised. He knew she lived in the Everfree, but she wasn't near where they were going. "Uh, beggin' yer pardon, but you gave us quite a shock."
Derpy flew up to her, looked her over, and turned back to Big Mac. "Big Mac! You got some 'splainin' to do! You'd think you'd have mentioned this to somepony by now!"
Big Mac shook his head. "I think it's a joke, there's no way I could have a foal, let alone one who's at least as old as me. Miss Zecora, what's going on here?"
Zecora, who had a smirk this whole time, replied simply, "I refer not to your body's natural age but to the true fact that you are a wise, old sage." The three looked a little worried. "Oh please, do not fret about your secret. I say you not only created the Everfree, but much more importantly, you have created me."
Trixie stepped towards her. "OK, you are making it sound like you're a golem or some kind of construct, but I can tell you're a living, breathing creature. The titans never created life forms on their own."
Zecora kneeled down, getting comfortable. "Perhaps I should reveal the past before conclusions are made fast."
The Everfree Forest was one of many forests the Titans had created. They were imbued with life, almost to a mind of their own. They would grow and prosper as any plant would. The Everfree was no different.
Until Discord came along. He caused suffering and misery, because he believed that to be his nature. But he didn't stop with ponies, oh no. Animals too could fall prey to his magic, as could forests as well. It wasn't that he twisted the forest, but it responded to his magic in that way.
However, the ponies were more aware and did everything they could to resist. They sought some way to undo the damage Discord was inflicting on them and the world. They unleashed powerful spells, some of which, due to its proximity, was absorbed by the forest. Those spells held powerful emotions. Fear. Anger. Hate. Rage.
Hope.
Nature has a way of finding a balance. The disharmony that Discord was using was being fought with more disharmony. The Everfree took all of it, converted it, and did what a forest does best. It grew something. A tree of crystal with six gemstones, five encircling one. With it, it began to push back Discord's influence.
Then 2 Alicorns came and plucked the fruit from it, wielding them as a direct line against Discord. What would have taken the forest hundreds, if not thousands, of years, was done in moments. The forest, now awake, had come to worry about these ponies. Such sudden changes could be disastrous for all. But the old forest was already learning. With the plundervine seeds below and the ponies above, it decided to help create a fulcrum for balance.
It took many years before it was ready. All that was needed was the last touches. From everything it had learned, it decided that something that appeared as not-a-pony but pony-like should do nicely.
And so Zecora was born.
"Much like you, I have kept a secret. I have not revealed myself yet. And I call you father," pointing to Big Mac, "not to confuse but for the life in me you have infused. I am the spirit of the old Everfree. I am Zecora and I speak for the trees!"
Trixie stared at her with a deadpan look and said, "I write one foal's book a couple centuries ago and today it comes back to haunt me."
Derpy ignored her and asked, "So let me get this straight. The Tree of Harmony was made by the forest blending Pony Magic?"
Zecora nodded. "That was very correct to a certain extent. But it has changed even more than it ever was before. The ponies who wielded their jewel filled them with power, over-full."
Bic Mac shook his head. "That's why we can't sense it with our abilities, yet we can sense it as ponies. It's not made from our old magics, it's something completely new. Converted magics infused with magic belonging just to ponies."
Derpy smiled. "Well, I guess we have to trust them. Let's get back before it's too late. I'm happy to leave this here." Big Mac smiled and started walking. Trixie remained behind though. "Trixie! Come on! We can't dawdle here forever."
Trixie shook her head. "We have a different problem now." Derpy, Mac, and Zecora look surprised. "The tree's power is spreading. It's growing. It will eventually spread across the world." She turned back with a solemn look on her face. "It's feeding off negative emotions and converting it to... well, harmony."
Zecora turned her head, puzzled. "What is this objection you bring? You make it sound like a bad thing."
Derpy nodded. "Yeah, what she said. Anger and hate will be gobbled up and turned into friendship and love! What's so bad about that?"
Big Mac hung his head. "Water that is too cold or too hot can't sustain life." Derpy and Zecora looked at him wide-eyed. "If it's too cold, everything freezes, nothing moves. If it's too hot, everything just boils in it. The world needs both to keep things alive."
Zecora chuckled. "I understand your analogy, but there is something you do not see. Perhaps this will help your fears abate. With all your planted crops, why rotate?"
Big Mac thought for a moment. "Well, if you grow the same crop in the same place over and over, eventually, the ground ain't no good for those crops anymore. Rotating them keeps... Oh! Planting different crops help keeps the dirt healthier!"
Derpy look confused. "I don't get it. What does that have to do with the Tree of Harmony?"
"Well, Discord and the ponies back then sowed a lot of disharmony. I reckon the Tree was a response to clean it all up. I mean, the forest? It doesn't look very happy."
Trixie smiled. "I see! The Tree is intended just for the forest, not the world. Too much harmony would be its own form of disharmony, so it's only working on the disharmony sewn into the forest."
"That is exactly what I meant when those energies were well spent," said Zecora. She walked out of the cave and back towards the Everfree, followed by three who would keep her secret with theirs.
Derpy sat down and smiled. "It's nice to know this trip was for nothing. Better safe than sorry. And we found we have a new friend. Ain't that cool?"
Trixie chuckled as Big Mac said, "Eeyup. Now please get off my head."