I have definitely not seen this thing in person. A black dragon of such a large size might be as big as the entire mainland China. Therefore, I should have seen this black dragon in a 'dreamland' or something of the sort.
Right, it was back during the Immortal Feast. Song Shuhang quickly found some memories of this black dragon.
After all, the image of this black dragon was so unique that it was rather difficult to forget it.
Song Shuhang remembered that when he was at the Immortal Feast, he and Fairy Rosy Cloud had participated in a food tasting challenge—at that time, the last dish in the competition had been a bowl of black stuff.
When Song Shuhang used the 'secret appraisal technique' to cheat, he accidentally identified the source of the dark material—the Ancient Evil Dragon. This appraisal had cost Song Shuhang quite a bit of blood.