- "I love my brother, Taiga..More than the world."
- —Yasuko Saejima
Yasuko Saejima first introduces herself by the alias "Lily" after negotiating a loan with Shun Akiyama of Sky. She under orders from Katsuragi to kill Shibata men and the head of Kanemura Enterprise,hoping her desire to see his older brother again,Saejima.
Stepsister to Taiga Saejima, who saved her life in the past after Saejima managed to get her to have a kidney transplantation when she was younger.
Yakuza 4 EditShe first appeared in Akiyama's arc where she asks for a 100 million yen loan. In order to secure the loan, Akiyama gave her a test: earn 3 million yen as a hostess in three days at Elise, Akiyama's own hostess club.
After passing the test, Akiyama calls her to meet up at the rooftop of Millennium Tower to give her a bag of 100 million yen. Akiyama explains the true reason that he is not testing her but also testing himself. Akiyama demands to know why she would go killing Shibata Family and Kanemura. Yasuko shocks but refuse to tell Akiyama the reason why and Akiyama let her go in case she return and visit Sky Finance when she pay him back someday. She leaves Akiyama alone.
Yasuko is later summoned by Tanimura who demanded to know what happened to her and his father the day before his father was killed twenty five years ago, but they got disturbed by Shibata men who won't let Yasuko out from their sights. While Tanimura fought the men, Yasuko ran away and later got kidnapped by some Shibata men who brought her to the dock. Shibata asked Yasuko why she killed some of his men and Yasuko said she can't believe she finally got three million yen as Arai raised an eyebrow. Shibata insist to know more,but Arai suggested they have to kill and he will take care of the mess. Shibata refuses and taking off her buttons,staring at her chest. Shibata mumbles how a man can be seduced by her as he want to touch her skin. Yasuko shocks watching Shibata got shot behind Arai aimed his gun. Yasuko is rescued by Tanimura and take her to his hideout.
Yasuko remained silent when Tanimura explains the hideout got nothing with cops as it safer around. Yasuko asked why would he hide her something. Yasuko explains what happened between her and Tanimura's father and Saejima in 1985. She reveals the reason why she killed those is she under orders from Katsuragi who knew her brother and give her a freedom if she killed those for him to prove Saejima's innocence. Yasuko realized that she get tired of his orders anymore as she give him her a bag of 100 million yen Akiyama lent her to have return back to him for him. Yasuko plan to head for Okinawa to find her brother in private prison alone.
Yasuko arrived at Okinawa, asking the local police about her brother's whereabout, but the police always told her that place doesn't exist in Okinawa and that she's wasting her time. She is approached by Kiryu and Hamazaki. They lead her to Tamashiro Family's old office. Yasuko learns that Hamazaki is Saejima's inmate friend and signs reliving. Much to her surprise, Saejima's already in Tokyo during the meet. They are approached by Saito and his private prison guards. Hamazaki protects Yasuko while Kiryu fight those guards. Hamazaki tells Kiryu to take her to Tokyo.
Yasuko and Kiryu arrived in Kamurocho. Kiryu took her to New Serena to meet Date. Yasuko explains the whole story about her and Saejima in front of Kiryu and Date. Yasuko sheds tears but doesn't care if his brother is a killer or not, only the matter that he is her brother that she loves. Kiryu tells Yasuko to stay with Date and he shall find Saejima for her. While Kiryu out looking for Saejma,Yasuko drugs the sleeping pill into the glass to Date as he sip and collapse on the ground,she run leaving New Serena. Yasuko is found by Akiyama and Tanimura and running to Purgatory down the sewer. Yasuko leaves these to Kiryu heading to Purgatory but got hostage by Ueno men. Yasuko and Saejima are taken to Kamurocho Hill.
Kida picks her holding her as negotiate exchange to the notebook Kiryu had. Kiryu holds Yasuko as Kiryu give Kida and walking to Katsuragi . Yasuko look at Kida aim a gun at them. Yasuko look kneeling over the edge to Kida got shot lying the lift down after Arai shot. Yasuko turns release Saejima. Yasuko notices Katsuragi picks his gun behind and shoot Saejima's arm left side. Yasuko rushes as he aim another bullet,saving Sajima got shot her back. Yasuko smiles telling Saeima to wait as she turns walking to him. Yasuko pick his gun that Tanimura gave her back before they fought Kiryu. Yasuko relives that Saejima is innocent but she states she got the blood on her hands then shoot him in the head before collapse. Saejima holds her into arm and yelling her name before she whispers her name softly before she died.
She wears a trenchcoat over a white shirt (and presumably a short skirt) and a pair of black heeled shoes.
She's depicted as a strong-willed female, willing to go as far as becoming a temporary hostess at Elise to get the 100 million yen loan. As a hostess, she shows a good competence, being able to score a great sales figure in just three days.