In 'i will just live on as a villain light novel', themes of morality are likely to be explored. The line between good and bad can be blurry, and the so - called 'villain' might have their own reasons and justifications for their actions. There could also be a theme of survival, as the character has to find ways to survive in a world that may be hostile to them because of their villainous status. Additionally, themes of self - discovery and personal growth may be present as the character evolves throughout the story.
Power struggle is likely a theme. As a villain, the character probably has to deal with other powerful entities, whether they are heroes or other villains, in a constant battle for power and influence. Also, identity might be a theme. The character has to grapple with being seen as a villain and how that affects their self - perception and relationships with others.