Black Star

To make things safer for the two of them, Rean and Kentucky flew as high as possible while keeping the Light and Spiritual Sense bending techniques active. With that, even if someone with higher cultivation than them checked the area, they would probably be too far away for their Spiritual Senses to break through Rean's skills. 

However, there wasn't much reason to worry. That's because the demon beasts who kept observing Rean's workshop back in the Demon Beast City refrained from entering it. They understood that there was a formation blocking their Spiritual Senses. Hence, they simply thought Rean was working on something he didn't want others to see.