Author's notes: I wrote this in response to a thread on the pokemasters forums, but now I suddenly thought of putting it here, since it really is a fanfic. So here we go.
Once upon a time, there was an island that was entirely inhabitated by Charmanders. They actually were a bit different from what they now are. They were smaller and walked on four legs, and had no Fire powers (and no flames on their tails). They all lived in harmony with each other, and the world was perfect.
One day, Polaryu was flying over, and unfortunately for the Charmanders, Polaryu landed on the island. Wherever Polaryu comes, everything freezes and it will snow. So suddenly, the Charmander island was all full of ice. The Charmanders were weak and froze to death. The ones that still lived barely survived.
But then, Thunderyu flew over and detected Polaryu on the Charmander island. Thunderyu, Polaryu and Volcaryu all hate each other and will fight whenever they meet. So Thunderyu and Polaryu started fighting right over the Charmander island. Thunderyu caused thunderstorms, Polaryu caused snow. Almost all the Charmanders died now. But once a lighting from Thunderyu hit a tree, set it alight and the tree fell. The few Charmanders that still remained felt the heat and came to the tree. The fire spread and the Charmanders were in a trap, with the forest burning all around them. All this heat made them stronger and more vulnerable to cold. They wouldn't have survived now even if they had gotten away.
When the whole forest had burned down, those few Charmanders were about to die of the cold, but what saved them was actually when Volcaryu arrived and caused the volcano on the island to erupt. The Charmanders got badly burned by the lava, but they made it, although now fire was the only thing that could let them survive. Water and cold became fatal to them. When the lava had cooled, they had only one place to survive: The volcano's crater. So they went up to the volcano, watched the three dragons fight, and dipped their tails into the burning lava to get heat. The tails were the only body parts they could dip into the crater without being in danger of falling in completely, which was still dangerous to them. After having their tail in the lava for so long, they ended up with a little ember of their own in their tails. The embers became flames, and because of the heat constantly provided by the flames, the Charmanders could go down from the volcano now.
But all this suffering had made them strong, and they ended up turning into Charmeleons. It wasn't much of a change, and the dragons were still fighting over the island. And the Charmeleons were in desperate need of food after all this, so they ate the frozen old Charmanders that had died long ago. When they were all eaten, the Charmeleons started fighting, killing each other for food. They reproduced, of course, and their offsprings were Charmanders like we know them today. Because of the fighting, the rule of the survival of the fittest came into play, and after a long period of time, the Charmeleons that lived now were very strong. But the battle of the dragons was still taking place high above them, and they knew they could never get their old peace back until the battle had stopped.
The strongest of the Charmeleons looked up at the battle. "I just wish I had wings... then I could go up there and stop their battle..."
But Jirachi heard his wish. And Jirachi made the wish come true: The Charmeleon grew wings and he turned into a semi-dragon. Not a real dragon, because Jirachi didn't have the power to turn a lizard into a real dragon, but almost a dragon. Additionally, all Charmeleons that from there on became as strong as the newly evolved Charizard would turn into Charizards too. The other Charmeleons weren't nearly that strong, but the Charizard flew up to the dragons and fought them valiantly to his death. The dragons didn't stop fighting, but this encouraged the other Charmeleons. One by one, they evolved after more fighting with each other, and flew away to other parts of the world, where they had offsprings and spread around, and lived happily ever after. How sweet.