Here's most of what we've gleamed at so far:
Ballos was imprisoned on the island by Jenka and was later forced by Misery to make the demon crown. Of course this meant that Misery was cursed by the crown to obey the crown bearers, although I doubt that was her wish. While we know little of the first two crown bearers, the third, known as Miakid, set alot of the events in the game in motion.
Miakid was sent to the island to take the island with robot soldiers and retrieve the crown for the governments of the surface. Now I should note that before Miakid's appearance there were a number of Humans residing on the island, a large number of which died defending the Mimigas from the robot soldiers. One theory states that the Cthulthu are the remnants of those Humans. In order to get out of a losing battle a number of Mimigas ingested red flowers as a last ditch effort to fight off the robot soldiers, and won, but could never return to normal. Then Miakid then took the crown for himself and started using enraged Mimigas to wage war. Curly and Quote were sent to destroy the crown, but didn't make it in time and were subsequenty defeated by the empowered Miakid.
At some point robot soldier team 9 attacked the core, but it could have been either an accident while taking the island, or purposeful in the sense that they wanted to get rid of Miakid after he took the crown for himself.
Of course little was known about how Miakid was defeated.
Later on during the 10-year gap between the red flower war and the start of Cave Story Arthur defended Mimiga Village from the Red Demon.