Strange Invasion, My Sister and I Depend on Each Other

[Weird Invasion] + [Single Female Protagonist] + [Thriller] + [Tear-Jerking] Grandma said that the sun used to be golden and the quilts that had been dried had a good smell. I have lived for ten years and have never seen the sun like that. That night when the blood moon came, the sky turned red. The sun has never warmed since then - it hangs miserably white, with a faint red edge around it, like a half-open eye. There is a reddish mist floating in the air all year round, and two-thirds of the people have been infected. They eat, talk, and call you home with a smile as usual until the things inside them wake up and use your face to open their non-human mouth. Chen Chen is an orphan picked up by the Chen family. His only relative is his sister Chen Nuan, who is ten years older than him. Chen Nuan is a preparatory ghost slayer of the Ghost Slayer Alliance. She awakened the A+ level ability "Eternal Brightness" - using her own vitality as a fire to heal, protect, and retain everything she didn't want to lose. The price is one use less time. She never said. Three days of family leave was the last time Chen Nuan went home. On the first night, grandma opened her mouth under the moonlight. The next dusk, my grandfather, who had been dormant for twenty years, showed his claws. In that blood and moonlight, Chen Chen awakened the S-level ability "Guixu" - using himself as a container to swallow all energy. The more you inhale, the less human you become. Grandma is gone. Grandpa is gone too. That home is gone. Chen Nuan took him out of the village and into the Ghost Slayer Alliance. From then on, they only had each other. She waved her sword in front to clear the way, and he used his body as a shield from behind.