One of my characters (fantasy genre) is from a noble family and her childhood was cut pretty short because her family had a huge target on their back during a revolution in her country.
Luckily, she was saved by some distant family members and their small guild.
Shai's childhood was kind of carefree, with "child" being defined as a Seafarer who hasn't yet begun their Sessions (so up until ten). Shortly after she turned seven, though, and got her defined seaform, it started going downhill. Her father didn't want her to be the heir to the House of Moray, and he had already disliked her. The next three years were basically finding small acts of rebellion against him, trying to juggle practices with political duties that come with being the Heir and trying to find time to still be a kid.
Owen is basically the polar opposite of Shai's childhood. His went until he was eleven, as his seaform was defined late, a rarity that prolonged his childhood and delayed the start of his Sessions. He was th perfect child, almost effortlessly, though a Shark's idea of perfect child is strong, follows orders and a little belligerent, so that isn't hard to live up to. He didn't have to worry about being the Heir, or pleasing his father. He had seven other brothers and sisters, so it was very rare he was alone with nobody to play with.
Luke's childhood was…. different. He still got the normal happy memories, fun experiences, etc, but they weren't so normal. His nana was a cryptozoologist who was convinced that Seafarers and sirens existed. She wasn't shy about imprinting this on her grandson, and got him to help her from a young age. His normal was walking home to find a sometimes normal, sometimes not sea creature in the huge tank on the dining room table, being "disciplined" by his nana. One of the highlights of those times was when he got to feed them. Somehow, he never wondered about how quickly they seemed to disappear.
Most recent character (Charlie) grew up in a dictator's concentration camp. He was starved, beaten, and worked to the brink of death, but never truly allowed to die. He has the number "314" burned into his left forearm, and many scars littering his body. After the dictator was taken down, he spent the remainder of his childhood trying to recover from this. This trauma led to him being a bit childish as an adult, as he tried to make up for the time he lost.
One of my favorite characters (Jody) lived a relatively happy life. She had a twin brother, a younger brother, and an older sister. She believed the Avengers were real until she was almost 9, and has always had a dream of being a hero. This leads to her being violent toward bullies and criminals, but she never got in trouble since there was never any actual proof of what she did (witnesses all sided with her). She's a really hyper kid otherwise, and goes on many day-trips with her family.