Orphans

"You're not the only orphan. This "Master" killed my father. We must avenge him" ~ Luna Ikapo Starflower to Gladion Scarface Skull

A recurring theme in fiction concerning heroes is the loss of their parents (usually both), normally at an early age, at least before their 18th birthday. Some orphans get separated from their families and find them. Some never even had parents and are clones born in a laboratory.