Whose Sister Is Not Invincible?

Once upon a time, Fang Chen, who was at the top of the boxing world, traveled back to his high school days. But the world has changed. The college entrance examination tests the seven ways of internal energy movement, the reverse entanglement principle of wind power, etc. He has no special powers and cannot learn ancient martial arts. However, he gained a system that could absorb other people's abilities and strengthen himself. Also, a sister who is cruel, talks little, is cute, and is invincible. Many times, my sister is easier to use than the system. Fang Chen said nothing and threw his sister to you. The enemy, suddenly! This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.