One of the main themes is heroism. It shows the characters' growth as heroes, facing various challenges and learning to use their quirks effectively. Another theme could be friendship, as the heroes often rely on each other and support one another in their battles.
Bakugo Katsuki is quite memorable. His explosive personality and powerful quirk make him stand out. He's constantly striving to be the best and his development throughout the story is interesting.
Friendship could also be a significant theme. In many stories like this, the heroes often rely on their friends. They support each other, work together to overcome difficulties, which is likely to be depicted in this light novel as well.
There could be a mentor - like character. This type of character usually has more experience and wisdom. They guide the younger heroes, and their words and actions can be very inspiring, leaving a deep impression on the readers.
The 'My Hero Academia Heroes Rising' light novel likely expands on the story from the anime/manga. It might focus on the growth of the characters as they face new villains and challenges in their hero journey. It could also delve deeper into the relationships between the students at U.A. High School.
The main characters would likely include Izuku Midoriya, who is also known as Deku. He has the quirk 'One For All' and is one of the central figures in the story. Bakugo Katsuki is also an important character, with his powerful explosion quirk.
I don't think it's difficult. The writing style is engaging and easy to follow. The story unfolds in a way that keeps you interested. Even if you are a beginner, as long as you have a basic understanding of the superhero and school - life genre, you should be able to enjoy reading the Bnha light novel without much trouble.
I'm not entirely sure as I haven't read it in detail, but generally, it might continue the story of the 'bnha' universe. It could focus on the growth of the characters, their new challenges, and how they deal with the complex world of heroes and villains.