In the early days of the Forest, the Gods were impressed by their own creation, and loved to enhance it by blessing it with even more beautiful gifts. When the Humanoid Races found the Forest, they were much in awe and respect of it's wonders, and praised the Gods for their creations. They also wanted to give gifts to the Forest, that they called the Holy Forest, and to the Gods that they loved. In the most beautiful and magical places in the Holy Forest, they built temples and shrines to honour the Holy Forest and the Gods.
The Gods saw this, and were pleased with their creations, the Humanoids. They wanted to give them gifts, like they gave the Forest gifts, and made magical and blessed items that they placed in the temples and shrines. They created magical cups and bowls that were always full of the most wonderful food and drink, and beautiful objects that could bless the Humanoids with health, strength and endurance. Some Gods created great weapons, that could be used in defense against the predators in the Forest, and charmed them so that they would want to return to the Forest if they were removed.
All the magical objects were meant for all worshipers and to be used by anyone in need. There were, however, people who wanted to own the objets and alone profit from their fine qualities. This greed would eventually lead to the Forest's downfall, but for a while in the age of the Holy Forest, the greed would be held back by a gift from Aiela the Wise.
Aiela the Wise was not in favour of the objects that unlimitedly gave powers to all who touched them. She suspected that the greed and vanity she had seen in the Humanoids would eventually lure them to steal the treasures of the Forest. Hoping to prevent this, she herself created a gift to the Forest and placed it in a temple that had been built by a blessed spring near the First Tree.
The gift's powers were many and complex, and to this day nobody has really understood them all. The gift shone with a bright light, almost blinding to anyone who tried to look at it. In the presence of the gift, the Humanoids felt calm and peaceful, and some claimed that they suddenly could find solutions to problems that had seemed impossible. Others were terrified, and wouldn't talk about their experiences. For this immediately visible power, the people called the gift the Heart and Mind Gem.
As the rumour of the Heart and Mind Gem spread among the Humanoids, people started coming to it in search for ultimate wisdom and knowledge. Clerics and philosophers sat in it's light and searched for a way to unlock it's powers. Warriors and thieves tried to pick it up, finding that whenever they tried to touch it it would vanish, avoiding all physical contact. For years people tried in vain to make the Gem follow their wills, only to find that the harder they tried, the less response they would get. People who had never seen the Gem before and knew nothing of magic or religion could gain insight at first sight of the Gem, and then not be able to tell others how, while the highest priests and wisest philosophers would only feel it's promising powers just out of reach of their mental capacity.
The one who finally unlocked the full strength of the Heart and Mind Gem was a young explorer who came to the Forest looking for Adventure, but also for a Clue to the greatest mystery that he was trying to solve: himself. As he came to the First Tree, he saw the glow of the Gem at the nearby shrine. It was not only curiosity that compelled him to approach the shrine and Gem, but also a calling he felt in his heart.
As the adventurer saw the Gem, he stopped and remained standing as if his legs wouldn't take him further. The beauty of the Gem spoke to him, and despite it's blinding glow he stared at it for a long while. The thoughts raced in his head, creating patterns he hadn't seen before. He felt naked in his own thoughts, suddenly facing memories and knowledge he had wanted to forget. He saw his own darkest thoughts, and the sides of himself that he despised. He also saw his good sides, and values he hadn't even recognized before.
This wasn't an unusual reaction to the Heart and Mind Gem. Those who entered it's presence with an open mind and without evil or selfish intents would have the deepest parts of their mind laid bare before them. Most people, however, didn't want to know it all, and would fight back the unpleasant thoughts, thus blocking the powers of the Gem and not gaining anything. Some accepted what they saw, and gained some insight, but fled before they had to face it all. None had, until now, embraced the flood and accepted more without restrictions.
Thus the young adventurer became the first to feel the Gem's power unleashed. He knew that he wasn't perfect, and welcomed the vision of his true self. He was also the first to draw from the unlimited source of peace within the Gem to help him remain calm as he faced the unpleasant sides of himself. He did not try to use the Gem. On the contrary, he let the Gem use him.
In a while he saw not only himself in the Gem, but also everything around him. He saw the Forest, and the First Tree. He saw things that were, things that had been, and things that would be, and he Understood. In the end, this became too much for even him to handle, and he had to let go of the Gem.
Afterwards, when people asked him how he had gained contact with the Gem, he couldn't explain it. He only knew that you had to have ultimate peace and no evil or selfish intents, and that you had to embrace your true self as it was shown to you, and also that if you tried this too hard, you would fail. There was no perfect method, no recipe.
He could also not fully explain what he had seen. He spent years trying to, wandering the Forest and preaching to everyone he met. He had experienced ultimate peace and knowledge. He had tasted the Gods' powers. He knew how the Forest should be treated, and how people should treat each other. He had seen the futures that would be, if the Forest was treated wrong.
Many people listened to him, and found the wisdom in his words. Some could even get closer to the Gem's powers after heeding his advice. In time, his followers formed a Cult that served and worshiped the Forest and the Gods, and tried to make peace everywhere they traveled. They acted as Peacekeepers of the Forest, and for a century after the Adventurer's death their deeds kept the violence and greed at bay.
As time passed, the Cult's faith faded, and with it their power vanished. Their shrines and temples fell in ruin, and the last followers grew old and died, not being able to recruit new adepts. Their actions had slowed the Darkness, but not halted it, and the Holy Forest would turn into the Ancient Forest as the Gods abandoned it, and into the Dark Forest as the Darkness was let in by the greed and selfishness of the Humanoids.