The novels originally featured illustrations by Tōru Yamasaki for the first six volumes, but Yamasaki was replaced by Sunaho Tobe in 2011.
Sunaho Tobe, having worked on the first two Dept. Heaven titles, and Yoshinori Iwanaga, having done the monster designs for the initial release of Riviera also return for Knights illustrations.
Artist Sunaho Tobe is quoted as saying that in the CG image for the Archangel, she drew inspiration from the designs of Yggdra Union.