Simca is a main supporting character in the series she is also known as the "Swallow". She is the secondary female protagonist of the series.

Kouta's busty next door neighbor and the editor-in-chief of Comic Splash, a B-rated seinen manga magazine. She shows two sides to herself: a ditsy woman outside of work and a serious editor at work. She is also known for recruiting novice artists and pushing them to their full potential, though there is a darker side to this through spread of rumors. According to Jiro Mineryu, a critically acclaimed author and a former student of Hinata, she tends to become attached to the author and his talents, leading to these misunderstandings. The rumor is further explained by Sayaka Jumonji, a former colleague of hers, claiming she has also "ruined" a few artists with her methods, earning her the nickname "The Novice Killer". She is the first to discover Kouta's full potential as a trigger-type artist. She drives a Ferrari 599 GTB Fiorano as her personal vehicle.

C.C. is apparently immortal, healing from any wound (implied to include beheading) with enough time. She also doesn't age. Apart from her immortality, C.C. has the ability to bestow people with the power of Geass, which manifests differently in each person but generally carries the ability to affect the minds of those it is used on in some way. The Geass sigil glows on her forehead whenever she manifests this power, and she has a similar scar on her left breast. It is hinted that many more like her exist, as shown in her memories of many children with similar sigils, and she suggests that the power has precipitated bloody conflicts in the past. Her powers caught the interest of Britannia, who imprisoned her for experimentation purposes.

Simca