The series revolves around Magnus Bane and Alec Lightwood, tackling many of Magnus's untouched secrets and stories from his past, his future, and his present and will follow the progression of Magnus and Alec's relationship previously unseen in the other books.
- The Red Scrolls of Magic and The Lost Book of the White were both narrated by BD Wong.
- The series title refers to the "eldest curses", one of them being Magnus Bane himself.
- The titles for the three installments were already decided before its announcement, but in September 2017, the order of the books were switched around to the current order.
- The books were initially planned to be released as an adult series, but after the first installment was done, the publishers thought it more accurate to publish them as YA, or young adult.
- The covers for the series were initially intended to all be illustrated by Anne Lambelet. However, by the time The Lost Book of the White and the paperback for The Red Scrolls of Magic were to be released, the publisher decided to switch the covers to being designed by Cliff Nielsen to match the other series.
- Cassandra Clare reveals titles of Magnus Bane series and more — TMI Source
- Cassie's newsletter regarding her updated book schedule
- "... is going to be published as YA," Cassandra Clare on Tumblr
- "They're all considered YA, regardless, because of the way publishing works." Cassandra Clare on Tumblr
- "I've already seen her design for Lost Book." Cassandra Clare on Tumblr
- "... when cover designs change in the middle of series, but these sorts of decisions are publisher decisions," Cassandra Clare on Tumblr
- "The paperback of #TheRedScrollsOfMagic will have a cover created by Cliff Nielsen, to match the other Shadowhunters paperbacks and feature Alec." Cassandra Clare on Instagram