Hayashi had seemingly snuck into Banba's office to kill him, but Hayashi intends to protect Banba from hitmen in order to get back at his employer, Zhang. Meanwhile, Saito narrowly avoids being tortured and killed due to a case of mistaken identity by Jirou and Misaki. Celebrating his good fortune with a night of revelry out in town, Saito awakens from a drunken stupor in a hotel room to find the body of a woman he's never seen before lying next to him.
and the killer is called that because he 
wears that mask and wields a katana.
والقاتِل يُدعى بذلك لأنّه يرتدي
ذلك القِناع ويحمل سيفَ كاتانا
und benutzt ein Katana.
y llaman al asesino así
porque lleva la máscara.
y llaman al asesino así
porque lleva la máscara.
et vu qu’il brandit un katana,
on l’appelle le Samouraï Niwaka.
Inoltre, visto che brandisce anche una katana,
è stato soprannominato "Niwaka samurai".
E o assassino é chamado assim
porque usa a máscara e uma espada.