The Doomsday Big Shot and Her Little Sidekick

Xu Renchu is the leader of a doomsday base, protecting the people in her territory.

One day, while diligently clearing out an isolation zone,

she discovers a group of zombies gathered around a completely naked young man. They aren't attacking him. They're doing that to him.

After observing for a while, she realizes his body seems immune to the virus. She rescues him and sends him to an official base.

Half a month later, a zombie horde breaks through her base. She and the high-level zombie invading it die together.

Xu Renchu is reborn.

It turns out she's a minor character in a raunchy zombie-horde erotica.

Her role is to watch the protagonist get it on from a third-person perspective and help move him to a medical test site so he can keep getting it on.

Now she's back at the moment the apocalypse begins, on her way to school in a taxi...

She immediately tells the driver to change course, heads straight to the protagonist's home, kicks open the security door, and rushes into the bedroom, where she catches the protagonist's bastard stepfather pulling down his pants.

Without a word, she chops off the stepfather's dick.

She holds up her knife and tells the protagonist, "You don't get to choose. Get dressed, gather food, and come with me right now."

The protagonist can resist the virus. If she gets him to a proper laboratory, they might be able to develop an antiviral serum.

Xu Renchu cuts down every zombie and man who charges at the protagonist with his huge dick out.

She doesn't notice the protagonist's increasingly dependent, affectionate gaze, because she doesn't pay him any attention at all.

He never resists or refuses. He's so helpless he can't take care of himself, and quietly helps her with the laundry, cooking, and every other daily chore.

On the first night after she delivers him to the laboratory,

he escapes and locks her up.

A pre-apocalypse martial arts instructor with off-the-charts combat ability, then the leader of a base after the apocalypse, female lead vs. a breathtakingly beautiful, delicate little flower of a male lead?

Theme: Don't judge someone through the lens of preconceived notions