Yuzuna Furuya

Chihiro and Mero's late mother, who died prior to the series. She was loved by her children and was remembered as being a good and kind person. She was turned into a zombie after her death (even takes care of Mero when she has a fever), but like Babu and the other resurrected, it is implied that she failed to contain her humanity, unlike Rea had.

Plot
In episode 9, Mero remembered her as an obscure, black-haired woman with bandaged fingers. Rea has a strong resemblance of her. It is highly suggested she was a zombie prior to her death due to her inability to tell temperature (like Rea) and parting with the reason that she loves them a lot, possibly hinting at her trying to leave before her zombie instincts take over. In the OVA, Chihiro finds a photo of her & quickly remembers a torn in half women believed to be his mother. It is also stated that she asked her husband to not speak about her.

She supposedly failed to retain her human personality. It is not revealed what happened after her "death" until Chihiro receives a letter from a zombie owl, a letter from his Grandfather. The letter contained secrets, and confessions, this lead Chihiro back to where they went camping before. Along with Babu, he went down the very same hole he and Rea fell into. WIthin the cave, he found a frozen body, which he believed to be Yuzuna, until he realized his mother was buried near the temple. The thawed zombie then introduced herself as "Otoki", Jogoro's second wife.

Otoki then revealed that Jogoro lived more than 100 years, due to the side effect of the drug. She also revealed Yuzuna's last wish after the accident, that she wants to take her family to an amusement park no matter what it takes, even if she had to become a zombie.

Trivia

 * She and Rea had some similar personalities, which also caused Mero to accidentally calling the latter "Mom".
 * Aside from frequent scenes showing her mouth and hair, no other facial features have been explicitly shown. However, the manga depiction vaguely shows that her facial features resembled that of Mero's albeit more mature.
 * It appears she had black hair, similar to Chihiro's.