The disclaimer applies to this character's history because there are mentions of: attempted murder via assassination, death and murder.
Derren was born in Australia on March 9th, a year before Erraline was born. Because of his status as a Royal Lunar Elemental, many disliked him (even though he wasn't even born into the royal bloodline). A big amount of those who disliked him were those who were passionate about the rivalries between the different Elemental Kingdoms.
Erraline and Derren's parents, Bianca and Connor Dange, were two fairly rich and loyal Australian Lunar Royals - both of New Zealander, French, English, Scottish and Irish descent. Derren was a descendant of English colonialists of Australia and New Zealand due to his father.
They were also saved by Christina Berne's father from being assassinated, but the siblings don't know this.
Two years after the birth of Erraline (and when Derren was three), their parents were killed in a massacre -- the culprits unknown. Conspiracy theorists presume that it was the work of a group of Solar Elementals who believed Bianca and Connor to be part of a cult. The infant children survived the massacre. Upon their deaths, Erraline and Derren inherited their fortune, which was placed in a bank vault.
They were placed into the care of a guardian, who took the children to live with her in Japan. Whilst Erraline gained an interest in Japanese culture, Derren became interested in movies. Sadly, the guardian died of an illness a couple of years later, just as the two were settling into life in Japan. The devastated children, who also did what they could to help the guardian because of her illness, were taken back to Australia by some Lunar knights.
Not much else is known about Derren's life by this point besides that he was enrolled into the Elemental Academy alongside his sister. The siblings, who were commonly mistaken for twins, initially had a hard time interacting with other people, especially because of the things they had been told about the other kingdoms and the death of their parents (when they got slightly older). Many believed them to be mute at first, but eventually, they were able to break out of this. Derren was slower in learning to become more social, whereas Erraline was fast.
Due to new changes made in the laws of the kingdoms, Derren was one of the royals to have a higher position as he went from a Lord to a Duke of the Lunar Kingdom.