|Height||165 cm (5'5")|
|Affiliation||Ashinaka High School|
|Occupation||High School Student|
|Base of Operations||Ashinaka High School|
|Anime Debut||Episode 1|
|Japanese Voice||Kanami Satō|
|English Voice||Michelle Ruff|
Sumika has long, dark blue hair that is styled into a traditional Hime cut, blue eyes, a slender yet curvaceous figure with large breasts.
Sumika wears the female uniform of Ashinaka High School, which is essentially a Sailor fuku. She wears a black shirt tucked underneath a dark blue jacket, which has a lavender bow on the front, as well as Sumika's green school pin. She wears a dark pink, frilly layered skirt with an additional dark pink bow on the back of it. Sumika completes her outfit with black stockings and fashionable, blue boots.
Sumika is a conservative girl. She usually stays quiet though Sumika can be friendly when spoken to.
One day, Sumika is about to have lunch with Kukuri Yukizome when she notices the latter eyeing fellow student, Yashiro Isana. Sumika listens as Kukuri states her plan to share her vegetables with Yashiro. She is then left alone when Kukuri chases after Yashiro to do her work. Kukuri is unable to give him her vegetables and ends up eating in the school cafeteria with Sumika, who takes a bite from her food. Sumika comments that Kukuri's in love.
Sumika later attends class with both Kukuri and Yashiro. Throughout the class period, she constantly glares at Yashiro. During one instance, she blushes with embarrassment when she sees Neko appear with a school uniform. At the end of the day, Sumika and Kukuri watch as their classmates continue production for the festival. Sumika expresses her wonder as to whether Kuroh Yatogami or Neko are actually transfer students like Yashiro said.
One morning, she helps paint wood for the school festival. When Kukuri appears asking whether there are students available to help with additional work, Sumika points out that they are all already busy. Furthermore, she pokes at how awkward it is between Kukuri and Sōta Mishina as they are walking away, though she quickly expresses exasperation when Kukuri still needs people to go with her. Sumika joins them to a supposedly vacant room in the males' dormitories, where they discover that the room is not as unoccupied as they are told. Sumika suggests that "that guy" is spending his time in the room, though she quickly loses memory of who the person in particular really is.
Later, she bears witness as the vacant room suddenly explodes while she is outside. Sumika nervously tells Kukuri that the person she was referring to most likely did not carry explosives inside.
She later helps Kukuri carry heavy bags across the school. During one trip, they both notice a Sword of Damocles hovering in the sky near the school's entrance, confusing them. To their subsequent surprise and fear, there is an explosion just below the sword-like figure; both girls respond by dropping their bags and holding on to each other. Sumika and Kukuri then relocate to their classroom where they do the same action as members of HOMRA intrude and being interrogating the other students, particularly about Yashiro. A worried Sumika asks aloud what is currently happening. The following morning, a loud siren rings across the school following a series of unknown explosions. Even more worried than before, Sumika begins holding on to Kukuri even tighter.
- The name Sumika means "clear, pure" (澄) (sumi) and "fragrance, fragrant" (香) (ka).
- Sumika's surname Inaba means "cause" (因) (in) and "flag" (幡) (aha/aba).
- Sumika loves anything that is cute
- Sumika's three measurements are B86 (Bust)/W55 (Waist)/H85 (Hip). 
- ↑ 1.0 1.1 1.2 1.3 K Official Guide Book A MEMORY OF KINGS
- ↑ K Anime: Episode 1
- ↑ K Anime: Episode 4
- ↑ 4.0 4.1 K Anime: Episode 9
- ↑ K Anime: Episode 10
- ↑ K Anime: Episode 11