Seiko is a kind and loving friend of Naomi. whether Naomi wants it, or not, Seiko is head over Heals for her... to the point where it can be both creepy, and annoying. she, of course means no harm, and essentially is no harm. her voice could sound very much happy going and open minded. she never is in one range of tone for too long. for preference, think of the English dubbed voice of Sasha from attack on titan but somewhat younger