Even when the manga encourages characters to live their lives to the fullest, there are moments where even the manga isn't afraid to show the sad side of the Zombie Apocalypse. The anime manages to turn certain moments that normally Crosses the Line Twice into a genuine sad moments.
- Worrying about Ohtori, Akira goes to her apartment where her company boss is a zombie, and Akira kills him. But to his horror, Ohtori was already turned, and confesses to her while holding his tears. He makes his confession, and immediately runs after zombie Ohtori chases him, and bids her farewell.
- When Akira goes out to get beer, he sees his neighbors, Mr. and Mrs. Kosaku, offering to get them something from the convenience store. When he returns, he doesn't see them, but the blood-stained apartment hints at a much darker conclusion. Akira upon seeing this, becomes somber and aware of his mortality- thus, plans to get enough done to die without regrets when such a fate visits him too. Unbeknownst to him however, the couple manages to escape.
- Akira grows close to Yukari, a flight attendant, and they discusses about their dreams. However, she gets bitten, and before she gets eaten, she tells Akira that being a flight attendant was her dream, and accepts her fate. Like the above, the anime shadows his face to show his sadness.
- Akira and the gang meet Masaru Kumano, a man who lives in the woods. After saving the protagonists from a zombie boar, he was busy constructing a treehouse, which fires Akira enough to fill that item onto the bucketlist. While they are busy, Kumano revealed that he wanted to build a treehouse with his son, but because of the zombie infestation, his wife and son were killed by zombies. Akira sympathizes with him, and the gang decide to help him finish the treehouse, fulfilling the condition on the bucketlist.
- As despicable as Kanta is, seeing his true desire to make more friends makes him a bit of a tragic figure. It gets a little more tragic when it's revealed that he was this close to being able to befriend Akira and co. but ran away from that opportunity that would have led him down a remarkably different path in life.
- Shoichiro Edogawa is an A.I. engineer who created the AI Hotel with Lambda Chop being one of his creations. He was also in love with Rui Saionji, and her death drove him mad, he had her mind uploaded into his computer in hopes to revive her. Then the group arrives to his hotel, he had Lambda drug the protagonists and had Shizuka and Beatrix in his lab he can upload her mind in theirs despite it potentially killing them. After Akira and Kencho saves the girls, Akira sympathizes with him, but helps him realize Rui wished to die. After the protagonists escape the zombie-infested hotel, Edogawa uploads his mind to his own server to be with her.
- Yudai Tsurumi was just a simple doctor whose life turned upside-down during the early stages of the Zombie Apocalypse. He then sees his wife and daughter killed by zombies while being stranded on the rooftop on live news. He then spends the rest of his life to find a cure for the virus, and hope to put an end to it. And then he meets Izzy, who became dull and unresponsive. After his researchers turned, he spent several months to keep himself and Izzy alive, and was close to Despair Event Horizon until he gets to meet up with the protagonists.
