Cassandra Clare may be best known for her YA series like Mortal Instruments and Infernal Devices. But soon, one of her most beloved characters will make the leap to the world of adult literature, too.

Clare will publish an adult trilogy about fan-favorite character Magnus Bane, EW can announce exclusively. Published by Saga Press, an imprint of Simon & Schuster, the first book in the series is slated for a November 2017 release, and will be co-written by Wesley Chu, author of The Lives of Tao.

“Over the years writing the Shadowhunter books, Magnus Bane has emerged as one of the most fun and fascinating characters for me to bring to life,” Clare says in a release. “He’s always had a lot of secrets — there are so many things we don’t know about Magnus, from the story of his first love to the secrets of his parentage, to the beginning of his relationship with Alec. All those are things I was able to touch on in The Bane Chronicles, but I’m excited to dig in even more deeply in these three volumes devoted to Magnus, his past, his future, and his present.”