The series primarily deals with three of the six worlds.

The series deals with issues such as death, sacrifice, and redemption.

The series often deals with social and health-related issues that affect young children.

The series deals with much violence, as the characters are all constantly put in dangerous situations.

The series dealt with subjects such as feminism and the generation gap.

The series deals with the protagonist's development of a conscience.

Over the years the series dealt with storylines controversial for the times.

The series deals with the everyday life of immigrants in Finland.

The series dealt with subject matter considered too mature for young children at the time.