Well, in the bite back series of novels, a common theme is likely the power struggle. Characters may be vying for power, whether it's over a group, a territory or some valuable resource. Also, friendship and loyalty play a part. Characters have to decide who they can trust in the tough situations they are in.
Since I haven't read the exact bite back series of novels, I can only speculate. There might be a young, brave character who is thrust into the middle of the chaos. There could be an older, wiser figure who serves as a mentor. And perhaps there are some characters who start off as enemies but later become allies as the story progresses.
Growth and self - discovery are themes too. Often when a character goes back to someone, they have changed. They have learned more about themselves, what they want in life, and they realize that the person they are 'going back to' is still an important part of their life. In 'Jane Eyre', Jane has grown and become more independent, but she still has deep feelings for Mr. Rochester and in the end 'goes back to him' in a new and more equal relationship.
Family also plays a big role as a theme in the amber series of novels. The family dynamics in Amber are extremely complex, with rivalries, alliances, and secrets among the family members. This family - centric aspect adds a lot of depth to the overall story and the characters' motives.
One main theme is survival. The characters are constantly fighting for their lives against the terrifying aliens. Another theme is exploration, as they often venture into unknown spaces where they encounter the aliens.
As I haven't read the Voron series novels, I can't say for sure. But it could be themes like adventure, friendship, or discovery, which are common in many novel series.
One main theme is the struggle against the mundanity of everyday life. Wilt often finds himself in situations where he is trying to break free from the routine.
One of the main themes is identity. Bourne is constantly trying to figure out who he really is due to his amnesia. Another theme is espionage and the shadowy world of international intelligence. The novels also touch on themes of betrayal as Bourne discovers that those he thought he could trust often have their own agendas.
One of the main themes is adventure. The characters in the Stargate novels often embark on exciting journeys through different planets and galaxies. Another theme is exploration, as they discover new civilizations and technologies. There's also the theme of survival, as they face various threats and challenges in the unknown regions of space.
Another theme could be self - discovery. The angels may start out with a certain understanding of themselves and their place in the world, but as the story progresses in the novels, they might learn new things about their abilities, purpose, and identity, which could be a major part of the overall narrative.
One of the main themes is often family. In Delderfield series novels, family relationships are explored in great detail, showing the bonds, conflicts, and growth within families. Another theme can be the passage of time and how it affects characters and society. For example, how the changing times impact the characters' values and ways of life. Also, the sense of community is important. It shows how individuals interact within a community, support or oppose one another, and how the community as a whole develops over time.