The answer is: "OST song" refers to the song in the OST. OST referred to the original music in movies, TV series, and other film and television works, and the song part was the OST song. According to the search results, some OSTs of movies and television works included some songs, such as the theme song of the TV series OST of " A Thought of Passing Mountains," many of Zhou Shen's OST songs, and Yu Kewei's Top Ten Classic OSTs. Therefore, an OST song referred to the song part of the original music in a film or television work.
'God Devouring Tower' was a fantasy novel written by the author of the Setting Sun Era. The story was about the young Qin Yi who lost his heavenly pulse because he was framed. However, he accidentally obtained the peerless divine pagoda, awakened the ancient God-devouring bloodline, reconstructed the divine pulse, and cultivated the Supreme Law. Finally, he rose up in adversity and displayed his unparalleled elegance. The novel was currently being serialised. The latest chapter was chapter 116. The main character, Qin Yi, had left the Heavenly Sword Sect.