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.
Well, it could be about the characters in the Gundam Wing universe behaving in a way that is appropriate for their age. Maybe it shows young pilots growing up and taking on more responsibilities as they get older.
The OST lineup for the second season of Celebrating Years had already been announced. Among them, Li Jian sang the theme song " In My Lifetime," Zhou Shen sang the ending song " Excuse me," Liang Long, Liu Duanduan, Zhang Haowei, and Guo Zifan performed the promotional song " Aiya." These songs would bring more musical elements to the second season of " Celebrating Years," adding more emotions and atmosphere to the plot.
Relena Peacecraft might also be one of the main characters in question. As she grows up in the fanfic, 'acting her age' could involve her becoming more politically astute and using her position to influence things for the better, which is a development befitting her age and status.
There was no specific information about the Gundam's killing move against the Gundam. The search results mentioned some ultimate skills in the Gundam series, but it did not specify what the ultimate skill was. Therefore, based on the information provided, I am unable to answer this question.
The OST lineup of " Celebrating the Second Season " included Li Jian, Zhou Shen, Liang Long, Liu Duanduan, Zhang Haowei, and Guo Zifan. They sang songs such as "In My Lifetime,""Excuse Me," and "Aiya." These songs were meant to continue the story of " Celebrating Years " with a melody and bring a new chapter to the audience. " The Second Season of Celebrating the Year " was an ancient drama adapted from Maoni's novel of the same name. It was starred by Zhang Ruoyun, Li Qin, and many other stars. The second season started filming on November 3, 2022, and was announced to be completed on October 17, 2023. It was aired on CCTV-8's primetime slot on May 16, 2024.