After recognizing the leader on the mural, Klein subconsciously suspected that it was something from his dream.
However, he quickly rejected the idea. This was because the unlucky Anderson wasn't someone he knew. He was also not someone that had left an impression on him. There was a low chance of him being the extension of his own dream.
And Anderson had clearly said that he became unlucky after seeing the mural. It was strongly tied to the mural, so it could only be the case that the mural was part of Anderson's dream!
As he focused and looked carefully, Klein quickly realized that the mural was somewhat different from the mural that Little Sun saw in the True Creator's abandoned temple.
The background here was a sea burning with golden flames, while the previous one was that of a desolate plain.