All members who participate, or once participated, in Supercell and their activities are listed here, along with information on each of them.
Ryo (musician, lyricist) 
Ryo is a musician and lyricist as well as the leader and core of the group. Besides composing songs for Supercell, Ryo has helped other bands and groups in the creation of lyrics for some of their songs, such as "Naisho no Hanashi" sung by ClariS , which is the second ending theme of the anime Nisemonogatari.
Shirow Miwa (illustrator, designer)
Shirow Miwa is a manga artist and illustrator. He's best known for the manga series Dogs, but he has also contributed illustrations to many tribute books and magazines, such as Square Enix's Monthly Shonen Gangan. Sometimes publishing his works under the circle name "m.m.m. + Gee", Shirow is an official member of Supercell.
Huke is a Japanese illustrator who is widely known for his ever popular, original character, Black★Rock Shooter, and being a part of Supercell. His character was a huge inspiration to Supercell's lead member Ryo, who wanted to use huke's design to create a song and music video by the same name, Black★Rock Shooter. Soon enough, this collaboration led to many opportunities for both parties, as the Black★Rock Shooter Universe expanded, receiving an animation adaption and other merchandise releases.
Redjuice/Shiru (illustrator, designer)
Redjuice, or known as 'Shiru' on Pixiv, is one of Supercell's members and the original character designer for the anime GUILTY CROWN. His speciality is drawing cybers theme. He uses SAI for coloring and Photoshop for backgrounds. His pen tablet is CINTIQ.
Maque (illustrator and animation)
Yoshiki Usa - at Wooserdesign (designer)
Hei8ro/Heihachiro (support in illustration and photography)
Guitar (support in illustration)
Guitar is supercell's backup illustrator. Guitar recently collaborates with Erico Lotus, and Tijeras.
119 was the second member of Supercell, the first being Ryo. Originally, 119 was the illustrator of the Hatsune Miku design that Ryo used in the PV for the song "Melt". As he used it without 119's permission, Ryo apologized. 119 though found great interest in the "Melt" PV Ryo had made and began working with him, thus forming Supercell. In the current, 119 retired from Supercell, but is assumed to be still active.