Serika is the shyest and quietest character in To Heart. She is very withdrawn and a very traditional Japanese girl as she is very polite, restrained, and quiet. She is so quiet that she even whispers when she speaks and can only be heard by Hiroyuki which he repeats so other people can understand. She is very nice even though she doesn't smile much and is so quiet.

Being a third year student (like a senior), she is about to graduate.

She is a daughter of the wealthy Kurusugawa family, which owns many companies (for example Kurusugawa Electronics, which built both Multi [HMX-12] and Serio [HMX-13]). She is incredibly rich as she has a chauffeur who drives her to and from school each day. Her twin sister is Ayaka, who is almost the complete opposite of Serika. She goes to a different high school (an all-girl school) and is much more self-confident and participates in extreme.

There are many rumors circulating about Serika, not only about her because she is rich but also because she practices witchcraft. She is the only member of the school's Occult Research Club and Serika practices witchcraft, casts spells and performs occult rituals. The "black magic" disturbs a lot of people which causes the distance and rumors about her. Hiroyuki had a large impact on her since he was the only one to get close to her.

She doesn't have many friends since she is so incredibly shy and quiet, is so wealthy, and practices magic. However, despite those attributes, she is very nice and Hiroyuki is one of the few to see that.