Kei Nijimura

Nijumura is the Higashikata Family household's housekeeper.

Personality
Nijimura typically performs all the average duties expected of a maid, and shows no emotion whatsoever. However, when Josuke asks her if she attacked him on the Higashikatas's orders, Nijimura reacts harshly to this, calling her masters "the goddamn Higashikata's". She also threatens to kill Josuke should he approach Holly, though seems to do so more out of personal reasons, even shedding tears and becoming more emotional.

After Josuke finally gives into her demands, she breaks down and reveals that they knew each other in the past, and is surprised that the protagonist has really lost all of his memories. She also reveals to him his quadruplicate eyeballs and duplicate tongues from the seams in the organs.

Synopsis
Upon entering the Higashikata household, Josuke is coerced into taking a family photo. Nijimura appears and attempts to remove his hat, causing Josuke to feel threatened, and ask who she is. Norisuke Higashikata IV answers for her and introduces her as the Higashikata family's housekeeper. When Norisuke shows Josuke around the house, he tells him that if anything is needed, he simply needs to ask Nijimura.

Later on, as she helps Yasuho Hirose exit the premises, she relays a message from her employer stating that Yasuho was not allowed near the Higashikata's house again. The next day, Josuke finds her in the kitchen serving breakfast.

Later, it is revealed that Nijimura is not only the user of the black biker stand, but that she is the daughter of Holly Kira. After a struggle, she revealed that she was not an enemy, but an ally, and reveals the seam on the protagonist's eyes and his tongue, revealing that he not only has 4 testicles, but also 4 eyeballs and 2 tongues.

This leads her into explaining to the protagonist  that is he not an actual person, but rather a fusion of her brother, Yoshikage Kira and one other person. This was due to the strange ability of the Wall Eyes, which can swap the genetic material of any two objects that are buried under the ground near them. She tells the protagonist the key to solving this mystery is through the Higashikata Family and their secrets, which is the main reason she went undercover as their maid.

Trivia

 * As she shares the same last name as Okuyasu Nijimura and Keicho Nijimura, it may be assumed she is the Jojolion counterpart of at least one member of their family.
 * The star-shaped birthmark on her shoulder, in the same location as the protagonist, and her statement that she's Holly Joestar's daughter reveals that she too is a descendant of Johnny Joestar.