In the anime, Taromaru had an expanded role as he was found by Kurumi in the mall. He is later taken in by the School Life Club members as their "mascot." He had more of a role as a supporting character in the Gakkou Gurashi! anime adaption.
Taromaru was a small Shiba Inu puppy. He had light brown-colored fur and brown eyes. Inside his ears were white fur, which also appeared on the tip of his paws and tail, under his belly and on his lower face. He also had a red collar in the anime.
In the manga, Taromaru's personality was not shown much. But he seemed to be a lively puppy and was happy when Yuki patted his head. When he succumbed to his infection, Taromaru got violent.
In the anime however, Taromaru was notably an intelligent and tolerant dog, putting up with anything Yuki may have done to him and being able to open doors and escape. In the anime, he was able to avoid infected citizens and escape to the safety of Kei and Miki. Though Taromaru is tolerant of Yuki's good intentions, when he began barking after Kei's departure as he didn't want her to leave the sanctuary. After Miki yelled at him, he held a grudge against her until shortly before his infection where he was seen cuddling with her in an act of forgiveness.
Generally, Taromaru was light hearted, enjoyed running around, and was usually seen in a happy mood. After he was infected he became volatile, barking and attacking Kurumi before he was sealed inside of a locked room. However, he seemed to have slight "consciousness", as he protected Yuki from other zombies when he already had succumbed to the infection. However, he performed these actions as zombies has a tendency to return to places precious to them, as Yuuri hypothesized. Taromaru did it because he was fond of Yuki and her hat.
In the manga, according to Yuuri and Kurumi, in chapter 17 (Dog), Yuki found Taromaru. Even though she just found him, Yuki was seen being very fond of him and wanted to take care of him until his owner "came back". When Megumi said that the owner had "picked up" Taromaru, Yuki was a little disappointed but hoped that Taromaru (the name that Yuki gave him) was doing fine.
In the anime, however, their relationship is expanded. While he was very playful with Yuki. He generally outwitted her and would escape whenever she tried to catch him. Taromaru also "saved" Yuki when she was being attacked by other zombies, even though he was already infected. Taromaru also was fond of Yuki's hat and Yuki became very sad as she cried when Taromaru died. Since Taromaru was also an important friend of Yuki's, she placed her precious hat over Taromaru's grave.
In the anime, after upsetting Taromaru at the mall by yelling at him, Taromaru started to dislike being around her, and preferred to be with the others girls instead, much to Miki's disappointment. However, Miki still cared for Taromaru and was seen being relieved and happy when she saw that he was also safe when the School Life Club members rescued her. That was until Episode 9, where Kei's CD player gave him enough reason to play with her. He also allowed her to hug him, where he was seen cuddling with her as an act of forgiveness. Moments before dying, Taromaru gave Miki a big smile, which Yuki said could be perceived as a "thank you", which shows that Taromaru did consider Miki as someone close to him before his death. Since Miki had known Taromaru the longest, she was seen being sad and speechless upon his Taromaru's death.
In the anime, Taromaru sometimes feared Yuuri when he was breaking a rule where would flee back to Yuki in result. Yuuri also sometimes would wash and dry him, which Taromaru liked. But Yuuri didn't like when he and Yuki would run in the halls. However, Yuuri was seen being very sad as she cried when he died.
In the anime, when the School Life Club members arrived at the mall, Kurumi found Taromaru. Taromaru was also very playful with Kurumi and she would sometimes wash him like Yuuri. When Kurumi saw Taromaru as a zombie, she became very shocked and sad as she couldn't believe her eyes. Even though he tried to attack her, Kurumi was unable to harm him. When he died, Kurumi shed tears.
In the anime, when Miki and Kei were at the mall, Kei saw Taromaru and played with him. Later, an elderly woman, Taromaru's owner, came along, and introduced Taromaru, and then walked off. After the outbreak started, Taromaru took shelter with Kei and Miki. He seemed to be fond of Kei as he began barking when she leaved the sanctuary, meaning that he didn't want her to leave.
Yuuri told Miki that Yuki found Taromaru and brought him to the club room, much to their others shock. This happened before the start of the series. When Megumi Sakura saw that he had been bitten, but yet to succumb to the infection, she said that it was a bad idea to have keep Taromaru. Megumi explained to Yuki that he already had a owner and that he would be staying with her, much to Yuki's disappointment. When Taromaru succumbed to his infection, Megumi threw him out, but he still occasionally attempted to get into the club room due to his residual memories of the club. If he was put down by Kurumi or not, is still unknown in the manga.
Taromaru was first seen with Miki Naoki and Kei Shidou while they were trapped inside the mall. After Kei left the mall, Taromaru proceeded to wander out of the "safe zone" as well. He wandered around the mall until he was found by Kurumi who was looking for canned food inside a derelict supermarket. Taromaru followed her to where the other members of the School Life Club where hiding. Yuuri then checked the dog for possible infections before Yuki was allowed to hold her. Taromaru, along with Miki joined club and stayed at Megurigaoka High School with them.
Yuki popped into the room with a puppy. Megu-nee had done a body inspection and found that he was unfortunate in which he already had a bite mark around his neck. Because of this, Megu-nee had claimed that she'll watch him until the owner returns. Sometime later, Megu-nee writes that she wasn't sure what to do with him, since his infection already got to the best of him. More time later, Yuki was told that the owner had returned to pick him up. In response, Yuki hopes that Taromaru will be doing fine without her.
Kurumi explains to Miki that Megu-nee had probably just thrown him out or something, but that it didn't end there. Continuing the story...
It was during a lunch break that Yuki heard a scratching sound by the door. Kurumi assumes it was her imagination but checks anyways. Opening the door reveals that Taromaru had returned.
Ending the story, Rii-san hypothesis that the zombies will return to places that are special to them.