One of the main themes is adaptation. The heroes are summoned from their normal lives to a completely different world, so they have to adapt to new cultures, magic systems, and social structures. Also, friendship and camaraderie are important themes. They often form teams or groups with other characters and rely on each other to overcome difficulties. In addition, the theme of power and its abuse or proper use is often explored as the heroes gain more and more power in the new world.
I'm not well - informed about the 'hero summoned 777' light novel. However, in general for such light novels, the plot often starts with the summoning of the hero. After being summoned, the hero usually discovers that they have unique powers or abilities. They are then likely to meet different characters, some of whom become friends or allies, while others are enemies. The hero might be tasked with saving the new world they are in from a great danger, like a powerful dark lord or an impending apocalypse. The number 777 might play a role in the hero's journey, perhaps as a key to unlocking a powerful weapon or a secret passage.
The theme of sacrifice is also quite common. The hero may have to sacrifice something, like a relationship or a part of their power, to defeat the archenemy. In addition, the exploration of different worlds or settings is a theme. Many 'archenemy and hero light novels' are set in fantasy worlds, and the hero and archenemy's interactions are influenced by the unique rules and cultures of those worlds. This can range from a medieval - like fantasy world to a post - apocalyptic world.
One common theme is the idea of the underdog. Orc heroes are often underestimated in their worlds, but they rise above it. For example, in many novels, orc heroes face discrimination from other races but prove their worth through heroic deeds.
Betrayal is a common theme. The hero is often betrayed by those they trust, like friends or allies, which leads to their abandonment. Another theme is redemption. The hero tries to redeem themselves or prove their worth after being abandoned.
A common theme is self - sacrifice. Characters with hero syndrome often put themselves in danger to save others. For example, in many such novels, the protagonist will jump into a fight against powerful enemies to protect the weak.
One common theme is the struggle to adapt to normal life. After being a hero with a lot of action and excitement, the retired hero often finds it hard to fit into a normal, quiet life.
One common theme is redemption. The fallen hero often has to find a way to make up for their past mistakes or misdeeds. Another theme is the loss of innocence. They have typically gone through some kind of trauma or made a bad choice that led them to fall from grace. Moral ambiguity is also a big one, as they may not be completely good or bad anymore.
Well, the theme of survival is quite common. Since the characters are in a new and often dangerous world, they need to find ways to stay alive. In 'No Game No Life', Sora and Shiro have to win games to survive in the world they are summoned to. Another theme is the concept of heroism. Whether they like it or not, many of the summoned characters are thrust into the role of a hero, like in 'That Time I Got Reincarnated as a Slime' where Rimuru becomes a leader and a protector. And the theme of moral choices also exists. In 'The Rising of the Shield Hero', the protagonist has to make difficult moral decisions in the face of the unjust treatment he receives.
Self - discovery is also a key theme. The anti - heroes usually start with a certain view of themselves and the world, but as the story progresses, they change. In 'Grimgar of Fantasy and Ash', the characters learn more about their own capabilities and limitations as they face different challenges, which is part of their self - discovery journey in this new world.
A prevalent theme is redemption. Sometimes, the demon king may not be entirely evil, and there could be a chance for him to be redeemed, or the hero may have to struggle with his own dark side. Also, friendship and loyalty play a part. The hero often has comrades who support him, and the demon king may have his own followers. Their relationships within their respective groups are important aspects. In addition, the theme of sacrifice is often seen. The hero may have to sacrifice something precious to defeat the demon king or vice versa.