The spinoff manga, Magi: Adventure of Sinbad will air in Japan in April 2016.
The manga’s popularity already inspired 5 OVA episodes that were previously released alongside the manga volumes in 2014. Anime News Network lists the cast:
“Daisuke Ono is returning from the main Magi television series and the OVAs to play Sinbad. Other returning cast members include Akira Ishida as Yunan, Tomokazu Sugita as Drakon, Ai Kayano as Serendine, Katsuyuki Konishi as Badr, and Yōko Hikasa as Esra, Keiji Fujiwara as Hinahoho, Takahiro Sakurai as Jafar, Ayumi Fujimura as Pipirika, Takehito Koyasu as Barbarossa, and Hiroki Touchi as Baal.”
Magi: Adventure of Sinbad is a spinoff of the original Magi manga created by Ohtaka. Adventure of Sinbad focuses on Sinbad’s journey to becoming a king and takes place 30 years before the story of Magi.