I'm Just a Passerby, and My Combat Power Is Off the Charts, Right?

Chen Zheyan travels to a hodgepodge world. He is not the protagonist, nor the villain, nor even a supporting role. He is just a passerby. In this world where the protagonist is everywhere, how can he ensure his own safety and live the life he wants? "System, it's time to check in. Where's the reward?" "Ding! Reward the host with eternal immortality." Chen Zheyan laughed happily when he heard this. Who said passersby can't be invincible? Who said that? This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.