The home town where the character lives is destroyed, there is little loss of life. However, after the disaster passes, the area is rebuilt and becomes more prosperous than ever before. (work with your DM to determine details)
Martial training: In adolescence you trained with the weapons of your people and learnt how to use them proficiently (work with your DM to determine details)
Approaching adulthood you experience wanderlust and decide to travel, roll 1d6 to detirmine years spent travelling and think about where your character might have gone. (work with your DM to determine details)