The events of 10 years ago go something like this :
Scientists and Mimigas coexist together as they discover the secrets of the island, or study their culture.
At some point in time, the great secret of the island... the Demon Crown is discovered by some of the scientists. This information is passed on to the surface.
It is unclear, but some countries of the surface desire the power of the crown for some reason. However, this is not the desire of all countries. Quote and Curly are sent to destroy the Demon Crown, while the countries that desire the crown send a force of robots to gain the crown.
Miakid is probably a human who seeks the crown. Perhaps in charge of the invasion.
The invasion is not necessarily violent. Not at first. Robots are sent to the island to find the crown. Mimigas may know the secret of the crown, but now refuse to tell. Or perhaps the Mimigas now know of the scheme and desire to protect the crown, knowing the consequences...
At some point, the robots are given the order to tear apart the island, to find the crown. Some of the human scientists band together with the Mimigas to defend them, and the secret. But, the robots are killers and kill many...
Quote and Curly at last arrive upon the island, they have been sent to destroy the crown before it can be taken. They discover the island to be torn apart, and countless Mimiga dead... Their struggle to find the crown and destroy it before Crown is used begins.
Between the time the robots first invade and the time that Miakid gets the Crown, Jenka offers the Mimiga a way to fight the robots. An evil flower that has the power to turn their rage into true power... The Mimigas embrace the flower and use it to fend off the robots at last. But...
At some point Miakid gets his hands upon the Crown. The robots task is done. Whether Miakid is a loyal officer of the countries that attacked is unclear. It is possible, that instead of retrieving the Crown as ordered; the Crown seduces Miakid to don it. And just like the red power of Ballos, it begins to corrupt Miakid. Misery and Balrog are now awake, and they offer Miakid a grand plan to take the world...
Perhaps Miakid had secret feelings of discontent against the world. A world that relies on robots to wage war... It is uncertain.
The real tragedy begins when Miakid learns to control the crown to use the remaining Mimigas to begin a plan to wage war upon the earth, using the island as a base.
The battle against the earth begins, and Quote and Curly finally confront Miakid, Misery (and probably Balrog). They are able to injure Miakid, but something critical happens.
Quote and Curly's fate are unknown.
The plans Miakid started continue, and cause war to spread on the earth.
Miakid dies mysteriously.
The war comes to a close, but for some reason the island is left alone.
Did Jenka make a deal, or have an ace up her sleeve? Did the rest of the countries punish the countries that attacked the island? The details are unknown...
10 years later, a group of scientists and a Doctor arrive at the island. At some point the Doctor discovers the Crown and the rest is history...
@Brickman - I wish you luck in your prequel! As long as you don't take the title I've been saving for my prequel story... Cloud Story