Rei has never left the forest area around his house, as such he has never seen the outside world. Out of chance, he suddenly meets the young Kanon Usui in the forest after she lost her way. She would later be found and returned to her parents by Ren. Sometime after returning Kanon, Brigitte "caught" Ren and introduced father and son to each other, quickly assuming he wanted to reunite as her lover and as Rei's father. Though it's clear by he mostly likely wants nothing to do with her.
Rei on the other hand is shocked to meet his father and know Kanon was his cousin. It's unknown if he ever met his father's relatives. Though judging by the shock of the meeting he most likely hasn't. It's equally unknown if he'll meet the rest of the Marker family.
- Approximately 14 years after the birth of his aunt Anjuu, Rei was the first child to be born in the Japanese vampire society, in which the women had been sterile for a long time.
- The reason would possibly be that his grandmother Calera and his father Ren had inherited the Armash bloodline from his great-grandmother Cecilia Armash.
- Since Rei's only appearance was from the extra chapter "Lost Girl in the forest of Braunlich", his name was only referred as "Rei" without actual surname. Since Rei's name (玲) was written in Kanji, this can be assumed that his full name was in Japanese, possibly with his father's surname (Maaka 真紅).