Dark wood

it has every possible threat in the world all put into one little forest. there is an old legend that one who goes to the center of the forest can discover the secret to eternal life and limitless power over the creatures dwelling in the world. Magicians centuries ago discovered the power and tried to take over the world with it but 3 small witches and wizards put a spell over the woods and caused the wizards to flee without the book. The 3 spell-casters then cursed the evil ones so they could never return. the evil ones then searched for others to enter with pure souls to retrieve the secrets again for them and allow them again to rule.