Li Yan followed closely and witnessed a segment of abstract light and shadows, known as "As Is Heard".
Unlike texts filled with a lot of subjective conjecture and judgments, these "As Is Heard" recordings, made by Earth Endurance, had to be things seen by Yan Fu Esteemed Walker themselves. The lengthy text narratives prior had to be based on these "As Is Heard" recordings. And together with the text narratives, they were to be placed in Mother Crown, for future generations to study.
By the way, what Li Yan saw in Abyssal Mouth, such as the Wingless Emperor, remnants of the R'lyeh scholars, and even the nest made of Soul-forgiving Water, was also recorded and placed in the first layer of Mother Crown. Named "Feather・Bing-Zi One Hundred and Twenty-Eight, The Wingless Emperor's Nest Sole Witness, Author: Li Yan."