Notice: A Caution Against Travelling to the Heart

So. You want to go to the Heart.

We've all been there, trust me. The promises of endless knowledge of the world, the wonder of the origin of magic. And I am here to tell you that it is not worth it. I went to the heart once. I ventured into the caverns, the taste of new knowledge tantalising as it drifted in the very air. As my expedition grew nearer, I knew that I would soon be able to return with all of the secrets of the world. Definitive answers to age-old questions, settlements to arguements from ages past. I was so sure that this would happen, that I did not stop to think - why would I be the first? If it was this easy, to just head down here and figure out everything, why was it me that was going to succeed, and no one who had come before me.
Alas, I did not ask myself this question. So I want you to ask it to yourself. Why am I the first?

Fate of the Expedition

If that has not served to warn you away, perhaps I should tell you of the expedition I went with down there. We were five in number, strong, limber, and smart. We brought all of the equipment we thought we would need and more. visemeters, directional aids, backpacks stuffed to the brim with medical equipment. We would have been prepared for another War of World's End, with all that we had. And we were efficient packing it - we were all well able to carry our equipment with ease.
It was three weeks before we got to the heart. We were running about a third of the way through are food reserves, and we saw a faint green glow at the end of our tunnel. We were elated, and we rushed to the source of it immediately. And oh, was it magnificent. To see the very thing that gives life to the entire planet, the heart of the world herself. The origin of each and every one of us, the provider of blessings. This was what we had waited weeks and weeks to see. This was breathtaking, resplendant.

If only we had turned back here.

But no, greedy for knowledge, we kept going. We were looking for the fabled Keepers, a society of ancient knowledge and magical talent far beyond ours. The stories were to be marvelled at.
It only took us a few days to find them - but they were not at all what we imagined. Mangled, ugly creatures, morphed by the overbearing presence of magic. Speaking in groans, and grumbles. But the worst part? They looked like us. Like a mockery of us. They were no fabled creatures of legend - they were zombies. Imagine, for a moment, that you were here in my shoes. You have been searching for weeks upon weeks, for the promise of long forgotten knowledge. Imagine, you find what you are looking for. You're face to face with the very thing that could give you all the answers you seek. But you look into its eyes... and it's a parody of you. Something old, mangled, destroyed almost to no recognition. These creatures could not have the knowledge that we believed that they would.
I wanted to leave right then and there. Forget everything that had happened, and turn back. I wanted to scream and yell to the world that they were not all we thought they were, they were husks of what we once were.
But my colleagues wanted to stay, and so I indulged them. Perhaps these creatures truly were the mythologised folk that collected and shared their knowledge to the world.
We were brought into their community, and there were only more of these husks, only confirming my beliefs. They lived in ramshackle huts, gathered around mushrooms to stare at them while they grew. Their language was a horrifying amalgamation of grunts, groans, and drooling - if it even was to be considered a language. I went to sleep that night, uneasy, but determined to convince my colleagues to head back up in the morning.
Instead, in the morning, I woke up to a horrifying sight. One of the creatures stood above me, wearing the mockery of a face that used to be my friend. They seemed to be trying to pretend that they were my friend, no doubt into tricking me to some far-off place to murder me for food. It all made sense now. The most devoted to learning had never returned from their expeditions to the cave, their friends returning scarred and insane. These creatures subsisted off of the meat of outsiders. It was then that I knew I needed to get out.
I collected all of the gear that I could, grabbed the food that I needed, and I ran. I returned to the surface, hoping that my remaining living friends would be smart enough to follow.
They never did. I was the lone survivor of our expedition.

My Warning to You

I know that if you have your mind set on finding the heart and the Keepers, there is nothing I can say that will stop you. But all I want you to remember is this: when you meet the Keepers, do not let them fool you. Don't let them trick you into becoming their next meal.