Demon Souls

5 demon children were all born on the same day at the same time.
They each wear a necklace that binds their souls together. So if one of them dies, so does the rest of them.
The Oracles have been waiting for a day when they all turn 13. Dragons will start attacking the demons, and wipe out a demon town every day until everyone it dead. The dragons have gone insane (obviously), a demon who was banned from the Demon Society starts to control them.
It is up to the 5 demon children to stop this mad villain and save their race.
The only way to do that is to retrieve a stone that is on the other side of the world. It can make the villain stop being able to control the dragons.
But can they do that? Thousands of lives rely on 5 young children.