Quick answer — Kei Ishiguro worked on Chiikawa (Color Design), Sleepy Princess in the Demon Castle (Color Design), Monthly Girls' Nozaki-kun (Color Design) and 5 more anime.
Kei Ishiguro worked on Chiikawa (Color Design), Sleepy Princess in the Demon Castle (Color Design), Monthly Girls' Nozaki-kun (Color Design), Plastic Memories (Color Design), Engaged to the Unidentified (Color Design), WATATEN!: an Angel Flew Down to Me (Color Design), Mikakunin de Shinkoukei: Kamo Nikutte Midori-ppoi Aji ga suru no ne. (Color Design), Though I Am an Inept Villainess (Color Design).
