Marina is a young woman with a round face, and a beauty mark under her right eye. She has long, straightened brown hair that falls to her chest. Her bangs are parted to the side.
She wears a grey pinstriped jacket with a large black collar over a blue vest, and a dark blue pinstriped skirt with tights and high-heel shoes. She also wears a necklace with a ring pendant.
Marina is a kind and helpful person, being patient with Kiryu despite his lack of business experience. She is perhaps kind to a fault, as she fails to recognize one interviewee as a scammer intending to collect money for taxi fare. However, she is very passionate about her job, as well as extremely knowledgeable, and believes that their work against the five billionaires is helping the community for the better.
As well as being the secretary, Marina acts as Kiryu's business mentor. In addition to lining up some candidates for interview, she helps Kiryu conduct the interviews, helping him with things like what questions to ask. In the substory "A Watery Investment," she chastises him for making the rookie business mistake of falling for a pyramid scheme. She also sends Kiryu's postcards to Dolce Kamiya during the associated substories.
Marina keeps Kiryu in the loop as to when he is challenged by any of the five billionaires. After he defeats the five billionaires, the Finance King reveals that they were just pawns in his game to defeat Kiryu and take over the Kamurocho real estate market. The Finance King's former colleague Yamanoi goes over to confront him at his office, threatening him with a gun. Marina convinces him not to throw his life away by killing the Finance King, and gets him to put the gun down. She then reveals that she is in fact a police officer and the evidence she has uncovered is more than enough to put the Finance King away for a long time. The finance king then picks up the gun and threatens them, before Kiryu defeats him in a fight, which leads to his Dragon of Dojima fighting style revelation.
After the fight, Marina says that she will continue to work for the property business for the time being. She explains that as the other five billionaires have shown remorse and co-operated with the investigation, they will not be sent to prison. Instead, they will be given parole, which they will serve by using their expertise to help the property company continue to improve Kamurocho. She then says that given her experience as the company's secretary, she is best placed to be their supervising officer.