The main reasons why the theme of reincarnation in the other world was popular were as follows: 1. Unique setting: The theme of reincarnation in another world usually reincarnates the protagonist from one world to another. This setting is very unique and can attract the interest of the audience. This kind of theme usually involved different cultural, historical, political, and other elements to bring a richer viewing experience to the audience. 2. Rich characters: The audience can come into contact with characters with different personalities, backgrounds, and experiences in the reincarnation theme of another world. These characters could be ordinary people, celebrities, men, women, or people of different races, giving the audience a variety of character experiences. 3. Powerful battles: Powerful enemies often appear in the theme of reincarnation in another world. These enemies can come from a variety of different worlds and abilities to bring powerful challenges to the protagonist. At the same time, the audience could also enjoy the exciting battle scene and feel the intense confrontation between the characters. 4. Time travel: The theme of reincarnation in another world can also involve the elements of time travel to let the audience feel the story of different historical backgrounds. Such a setting could increase the interest and depth of the work to attract the audience's interest. In summary, the theme of reincarnation in another world had a unique setting, rich characters, powerful combat, and time-traveling elements. These characteristics could attract the interest of the audience and become one of the popular topics in the current animation works.