I don't remember the title of the manga but I remember some details about the manga.

I don't remember what monsters look like. But I remember reading that some survivors are trying to escape the monsters that are invading the city.

The main male character of the manga is a high school boy.

A schoolteacher with muscles convinces a group of people including a few high school students to follow him. One by one, survivors began to die. One dying survivor begged the teacher not to abandon him. Then the teacher kicked him away.

In the next chapter, the muscular teacher revealed he was expelled from school for hitting on a female student. He said the girl in the photo wasn't his daughter but his student. He starts to develop an interest in a high school girl who is part of the group of survivors.

In another chapter, the survivors ran to a theater where they met the theater owners who are an elderly couple.

In another chapter, when the survivors get inside a car to escape the monsters, one of them pushes the schoolgirl away. Then the teacher shoved him out and let the girl inside. The car goes away. A monster kills the one who is stranded.

A group of soldiers wipes out the monsters. They let the boy and the girl aboard the helicopter. But the helicopter is attacked by monsters, and it crashed down.

The teacher urged the boy to save the girl.

The teacher is infected and transformed into a monster. He began to dream that he was living with the high school girl as his wife and their baby.

That is all I can remember. Please help me remember the title.