The Beauty and I Kill Monsters and Level up in the Apocalypse

My name is Lin Wuyou, and just like my name, I am a carefree and handsome little brother. I was hit by a car on the way home that day. Just when I thought I was about to die, a beautiful sister appeared in front of me. Oh my god, that figure is amazing! The beautiful sister pulled me into a different space, got close to my face and said seriously: "Boy, do you want to be the savior?" I nodded wildly. Then she forced me to draw a lottery, and finally I got an alien pupil. The beautiful sister continued: "As for me, I will be your system from now on."