Saikano

Shuji
Shuji is one of the two main characters. He's a student at the high school in this anime, and had until recently been on the track team. He's well liked by his classmates and is quiet and stern most of the time, but he tries to be easy going. As the story opens, Chise had just a few days ago confessed to Shuji that she liked him, and to her surprise he said, "OK". They try to get to know each other little by little, but at first differences in their personalities make communication difficult. He has a lot of mental and emotional turmoil about what to do regarding Chise's augmentations and her feelings. Eventually they overcome that and fall in love. Fuyumi, a girl who Shuji found himself sexually involved with in junior high school, shows back up in his life and tempts him many times to be with her again. Shuji struggles to refuse her, but after Akemi's death, he is finally able to tell her that he can't be there for her anymore. After this, he and Chise elope in a neighboring town and live together with the love they had fought so hard to grasp finally in their hands for a short while.

Chise
Chise is the other main character. She's in Shuji's class, and had liked him for a long time before being dared to ask him out. She's timid and clumsy, and is a small, delicate girl. Her motto is to become stronger, and she has a habit of apologizing all the time. It wasn't long until, for reasons unknown to her, Japanese military scientists altered her body to be a weapon to use the in war that was consuming the nation. Her alterations scare her because she doesn't like the idea of killing people, and she is scared that the changes are making her less human. For this reason, she is embarrassed of her body around Shuji for a long time. During the time when she had broken up with Shuji (even though she couldn't completely free herself of her feelings for him) she sought the companionship of Fuyumi's husband Tetsu, who was a soldier in the military. He reminded her a lot of Shuji and treated her like a normal girl, while accepting her differences. That was important to Chise because she felt as though she wouldn't be any good to normal people in her condition. During and after her brief fling with Tetsu, she realized she just couldn't erase her feelings for Shuji and they spent two of her last weeks as husband and wife in a neighboring town.

Akemi
Akemi was a childhood friend of both Shuji and Chise, and was also on the track team with Shuji. She secretly loved Shuji since childhood, but could never feel comfortable telling him - especially since her best friend Chise also liked him. She revealed this to Shuji's friend, Atsushi, when he confessed his feelings to her. Since she knew she could not be with Shuji, she gave herself to Atsushi, but they both knew her feelings could not be changed. She was gravely wounded during the second large earthquake, and after confessing everything to Shuji at last, she died in his arms.

Atsushi
A schoolmate and friend of Shuji's, Atsushi had a crush on Akemi for a long time. The war and the loss of their friend Take led him to decide to quit school and join the military. Before leaving, he confessed his feelings to Akemi, and she agreed to let him call her his girlfriend while he was fighting. In a sad and ironic turn of events, he and Akemi die at nearly the same time; he in a crossfire at war, and her from wounds received during the earthquake.

Fuyumi
Fuyumi is a girl a few years older than Shuji. In junior high, she helped out with Shuji and Akemi's track team. During that time, she broke up with her boyfriend, but Shuji reminded her of her ex, and the two of them ended up having sex. Years later, she married Tetsu. After the war started and Tetsu had been away for a while involved in the fighting, she happened to run into Shuji again. Because she was lonely and scared, she clung to Shuji the same way she did when they were younger, seeking some kind of intimacy and security in him, but though he was nice to her and almost stayed the night with her, he ended up pushing her away each time because of his feelings for Chise.

Tetsu
Tetsu is Fuyumi's husband and an officer in the military. He is the only survivor of one of Chise's original assigned units, and slowly he began to develop a kinship with her. He later said it was because when she was depressed, she reminded him of his wife. Tetsu himself acts and looks a lot like Shuji, which in turn helps Chise warm up to him quickly. Tetsu is probably the only other person besides Shuji who is able to view Chise completely as a human being instead of an "Angel of Death" due to her frightening power on the battlefield. In his delirium before death due to multiple gunshot wounds, he only calls out for Fuyumi, even though Chise was the one who was holding him, showing where his true heart was. This might be where Chise decides to stop denying her own heart and go find Shuji, making it a very important experience for her.