 Bert Ljung is the main character.Bert starts as a 12-year-old child in the spring term of the 5th grade but later becomes a mischievous teenager discovering his own sexuality.From the book "Berts första betraktelser", the readers can learn that Bert Ljung was born on February 21, 1976, but there are a lot of anachronisms, with the later books largely following a floating timeline.