As seen in Yakuza 0, Nishikiyama started off to be very loyal and supportive towards his friends and family such as Kiryu and Kazama. He often hangs out with Kiryu, and frequently banters about his inadequate taste in fashion. Despite being forced by the Dojima Family to fight against Kiryu, Nishikiyama fought alongside his sworn brother many times and promised that he'd always be there. Nishikiyama also seems to worry about Kiryu for his reckless attempts against the Dojima Family. He also firmly believes that people can succeed in the world through appearance rather than substance.