Sayo Hikawa 氷川紗夜

Sayo is a third year student at Hanasakigawa Girls' High School and the guitarist of Roselia. She is the older, more serious twin of Hina.

Sayo sees being the eldest twin as more of a burden than anything. Ever since they were younger, Hina has always beated Sayo in everything; whereas Hina can master new skills with ease, Sayo requires a great deal of information before she can even begin to practice. As a result, Sayo developed a severe inferiority complex towards Hina. One of Sayo's main reasons for starting to play the guitar was because "it was something Hina wasn't doing".

A serious and fussy girl, Sayo is somewhat cold in nature, even towards those she is close to. She never cuts corners or accepts shoddy workmanship, and she tends to stubbornly deny liking or being fond of certain things, such as fluffy animals or french fries. In comparison to Hina, Sayo is stiff, sharp, and very stubborn when trying to do what she believes is best for others. She is very formal, addressing everyone by their last names, except for her sister and Tomoe. Like Yukina, she is prone to make snide or rude remarks, though often these remarks do not reflect how she actually feels.