Contains spoilers (including Spoiled by the Format) for the entire show. Browse through at your own caution.
Mirai Onozawa is one of the main characters of the show, and is the sister of Yuuki Onozawa. She, prior to the earthquake, was a rather pessimistic, ungrateful girl. After having to take her brother to a museum, she wished the world would just crack. She ends up getting her wish.
- Action Girl: Once the cataclysm begins, she starts to take things more seriously and has risked her life to save others several times.
- Animal Motifs: Frogs, which are her favorite animal. Interestingly enough, the Japanese word for frog is "kaeru"note , which is a homophone with the word for returning homenote .
- Break the Cutie: She's cute, her phone is cute, she has pretty nice eyes, but of course, she gets broken. She loses it once she finds out Yuuki is dead, and she was just imagining him. In fact, any time something emotionally traumatic to viewers happens, it's traumatic for her as well.
- Broken Tears: During one of the hospital scenes, we see her break down in tears after the doctor tells her and Mari of Yuuki's deteriorating condition.
- Character Development: In the beginning, she's grumpy, pessimistic, and a little selfish, but after seeing other people suffer in the earthquake and becoming very close to very ugly endings (ultimately receiving one in that Yuuki dies), she becomes more optimistic, grateful, and helpful.
- Conditioned to Accept Horror: This trope is so averted that it's not even funny.
- Dull Eyes of Unhappiness: When Yuki faints.
- Dysfunction Junction: Upon realizing and finally dealing with the fact Yuuki's dead, she has a complete breakdown.
- Heroic BSoD: After returning home only to realize that Yuuki has been dead for a while, she falls into a depression for the rest of the summer until Mari visits to talk her out of her funk.
- Limited Wardrobe: Except for the scenes where she's at school and the ending of the series, she wears the same outfit for most of the show. Justified, as the earthquake has obviously made it troublesome for her to return home and change clothes.
- Meaningful Name: "Mirai" means future. At the beginning of the show, she's not sure about her future, and things look bleak for the future when the earthquake happens. However, towards the end of the disaster, things to start to look the same as they were before except now that Mirai has had Character Development, she has a more positive outlook on it. It also means that unlike Yuuki, she will continue to live on, albeit Yuuki will no longer be in her life.
- Phoneaholic Teenager: She's constantly on her phone, leading Yuuki to affectionately deem her a "Cell Phonian".
- Sour Outside, Sad Inside: She's initially portrayed as a pretty sour girl with a hint of saltiness, but that layer is stripped permanently once the disaster happens.
- Tragic Keepsake: Her phone, which she thought she threw away and lost after an argument with Yuuki in the middle of the show. It turns out Yuuki retrieved it after she ran off from the argument, also writing a message in it, and Mari gives it to her in the finale due to Mirai accidentally leaving their bag with her. She also starts to tend to the tree that Yuuki planted at the very beginning of the show. All, of course, are in memory of Yuuki.
Yuuki is one of the main characters of the show, and the younger brother of Yuuki Onozawa.
- Annoying Younger Sibling: Mirai views Yuuki as this due to his peppy attitude clashing with her more pessimistic one.
- Cheerful Child: He's a perky, friendly little boy.
- Cynicism Catalyst: Also known as "Dead Little Sister". Mirai, having become more optimistic after reconciling with him at the Tokyo Tower, could've fallen back into cynicism after Yuuki's death, but instead has a Heroic BSoD before inverting the use of this trope.
- Death by Newbery Medal: He dies right before the end due to head trauma he had gotten earlier on when Tokyo Tower fell.
- Meaningful Name: "Yuuki" means courage. Despite everything getting worse before it gets better, he persists with a smile on his face.
- Too Good for This Sinful Earth: He is perhaps the most idealistic and optimistic character on the show, and he ends up passing away at the end.
A delivery girl that Mirai & Yuuki met at the museum. After it turns out they live near each other, the trio decide to travel back home together, with Mari hoping to find her mother and daughter.
- Biker Babe: She drives a motorcycle and is quite the looker.
- Broken Tears: She breaks down in tears after she sees the doctors put a black tag on Yuuki's body.
- Cool Big Sis: Mari's a nice woman who befriends the kids and tries to help them back home.
- Disappeared Dad: Her elderly mother lives with her and her daughter, but her father isn't mentioned.
- Good Parents: She's a very good mother to her daughter, Hina. Her experience taking care of her own child leads her to be a pretty good Parental Substitute to Mirai and Yuuki, as well.
- Her Heart Will Go On: Her husband died before the events of the series, but she's as strong as can be. She even says herself that her toughness is due to her husband's death.
- Nice Girl: She simply helps Mirai and Yuuki because it's the right thing to do.
- The Lost Lenore: She mentions a few times that her husband has passed away. The first time is when Mirai points out how strong Mari has been through the earthquake and its aftermath, Mari attributes her toughening up to her husband's death. Another time, when comforting Mirai about Yuuki's passing, she says that she was in the same state Mirai is in when her husband passed, but she kept going anyways.
- Parental Substitute: She has a daughter of her own, albeit younger than either Mirai or Yuuki. She acts motherly towards the siblings and even gets mistaken for their mother once.
- Someone to Remember Him By: Hina is this to Mari. Mari was in a daze and in deep grief when her husband passed, but she saw how Hina was growing and it kept Mari moving on.