The Sun Makes You Stronger, but There's No Daylight Here? !

Doctor, can I still be saved? " "Yes, let's get some sunshine. " A patient who opened his eyes and was sentenced to death by modern medicine found that he had traveled through time. The good news is that what the doctor said has come true. Sunbathing can really extend your life and make you stronger! The bad news is... He has arrived in an underground city where the sun is hidden! This is the City of Forgotten River. There is a brass exoskeleton that sprays thin steam, there is a cosmic divine machine that was eliminated after the interstellar war, and there is a madman named Yizhi who has transformed his whole body, but the only thing missing is sunlight. He had no choice but to risk his life in order to follow the doctor's orders and chase the light. Unknowingly, when he finally realized the freedom of using light, he also had countless titles on his head. Yan Tingwu, the romantic young man, dog butcher, cage champion, and underground emperor, said helplessly: "I really just want to bask in the sun. " (National martial arts + mecha + steampunk + space opera)