The first time they met was because of duty.
Casper was assigned to relay the news about the explosion on the island, and he had to approach the four youngsters who were busy talking with each other.
He was just a young soldier who was often seen as the wallflower in the army, and he often received a trivial task like that instead of being ordered to fight the enemy in the frontline.
The duty he received today sounded trivial, but that was actually important and probably would cause more pain if he wasn't able to deliver the news properly. That was why he looked so nervous the moment he started reporting the news to the four youngsters.
As predicted, the four people were shocked by the news, and one of them even almost fainted upon hearing the shocking news. He had tried his best not to hurt the people's hearts, but that wasn't an easy task.