Mika is a secondary character turn major antagonist who appeared in the Rika Behind DLC. She is an orphan who was raised in the same orphanage as Mina (Rika) and she is revealed to be the original mastermind behind the creation of Mint Eye.
Mika is usually depicted as a young girl with wavy mid-back length blonde hair and small green eyes. As a child, she is usually shown wearing an ivory-colored dress with long sleeves and a pink string bow around her neck.
While at the hospital, she can be shown in the hospital bed with the hospital uniform on, which is a light gray with the words "HOSPITAL" and "병원" written in a vertical format, as well as the shapes of a plus sign, and a circle split in four.
Her last appearance as a character has her wearing a dark pink turtleneck with perforated sleeves. The rest of her outfit is not shown. Her hair is also much lower at this point, even reaching her backside.
Mika grew up in the same orphanage as Rika who notes that she was adopted once before by “bad parents” who after some time returned her to the orphanage. Because of this she grew up resentful and with a belief that children don't need kind or caring parents but cruel and strict ones to prosper. She is also shown to be a highly devout Christian which she shows to the people coming to the orphanage in hopes of getting adopted. After Rika was adopted, Mika continued to stay at the orphanage until she reached 6 years of age.
She spends much of her teenage years in a hospital owned by Rika's adoptive father where she is diagnosed with cancer of the eyes. Rika, on a trip with her father, stumbles upon Mika and they share a conversation. Mika pretends to be fine and says she is going to study to become a nurse which is later proven to be a lie she told to calm Rika down.
Mika and Rika meet again in an unspecified location after which point she spends the rest of her days in Rika's apartment. At this point she has completely lost her vision to cancer. It's also noted that Mika was present at Rika's engagement to V, but that the rest of the guests present didn't notice her. After the engagement, she helps Rika come up with the concept of Mint Eye as an organization based on her idea that fear is the only way for people to prosper. She dies in the apartment a few months after telling Rika to be distrusting of V.
- The name Mika means "beautiful" (美) (mi) and "fragrance" (香) or "increase" (加) (ka).