The Inner Eye was a cultivation technique or divine power that was usually described as the ability to observe tiny things in the universe and grasp their essence. In some novels and legends, clairvoyance was considered an ability that surpassed the limits of human cognition and could be obtained through specific cultivation or spells. However, this statement had not been confirmed by the scientific community, nor had it been proven or measured by scientific methods. Therefore, it was unknown whether the Divine Eye really existed.
Honestly, I don't know when the TYBW manga starts. But you could search manga databases or ask in manga enthusiast communities to get the details you need.
Wu Zhu covered his eyes because his eyes had laser energy. They could shoot powerful laser light, which was very lethal. In order to protect the outside world from his eyes, he chose to cover his eyes. This ability was not easy to control, so he could only use the black cloth to cover his eyes. Wu Zhu's eyes weren't blind, but he had chosen to cover them with a black cloth to hide the lasers in his eyes. By doing so, he could hide his identity as a robot and prevent others from discovering his special abilities.
The TYBW arc's starting chapter isn't a straightforward answer. It could be different based on the manga version and region. I suggest looking at dedicated manga websites or asking fellow manga enthusiasts for the exact chapter.