In a prospering kingdom, there came tragedy. A dragon had taken residence in a neighboring mountain. It breathed fire into the forests, killing livestock and villagers. The creature was so large and fearsome to look at that that many fled the forests and sought refuge. The king was kind to his people and opened his palace to them, promising to end the dragon before any more lives could be lost. A reward was sent out to all the kingdoms, asking for help in defeating the dragon. Many tried and all failed.
So many died that the king forbid anyone from entering the forest or the mountains. A spell was cast on the border between the forest and the town, keeping the dragon from entering. Years passed and the dragon soon became legend, having not once been seen since the spell. The forest grew wild and the town prospered on its own again, growing towards the sea. All was well.
Until someone ventured into the forest again.
Your cliche monster/human line. This time, the monster is a dragon. Or are they really a monster or just a creature misunderstood? Perhaps both. I shall play the beastie in hopes that I can find a human to come and befriend the dragon instead of killing it, to see past the scales and fangs and yes, blood. Dragons do kill so let's not eliminate that.