One common theme is the idea of 'the other'. Since the alien is different from the human, there is often a sense of discovery and exploration. They have to learn about each other's cultures, if the alien has a distinct culture.
Another theme is acceptance. In these stories, the human or the alien (or both) have to accept the differences between them. For example, physical differences like an alien having a different appearance or abilities. And also emotional differences in how they experience and express love. It's about looking past the exterior and finding a connection on a deeper level.
Isolation is also a theme. The alien is often alone in a human world or the couple is isolated from society because of their relationship. This can add to the intensity of their love as they only have each other to rely on. It also creates a sense of mystery and a need for secrecy in many cases, which is a recurring element in alien - human love stories.
Another theme is the concept of adaptability. The human has to adapt to the alien environment, culture, and way of life. And sometimes the alien also has to adapt to the human's strange habits. It can lead to some really funny and heartwarming situations. For instance, in a story, the human likes to sing which the alien finds very strange but also endearing.
The theme of discovery is also prevalent. Humans are curious about aliens, and aliens might be curious about humans too. In stories like 'Contact', the main character is eager to make contact with extraterrestrial life and understand the universe better. Cultural exchange is another theme. Different species have different cultures, and when they meet, there can be interesting exchanges of ideas, values, and technologies.
Common themes in human love stories include passion. Lovers in these stories often have an intense and all - consuming passion for each other, such as in the case of Cleopatra and Mark Antony. Another theme is the struggle against society or family. In Romeo and Juliet's story, their families' feud was a huge obstacle to their love. And the theme of redemption can also be found. Sometimes, a character in a love story may try to redeem themselves through their love, like in some modern - day love stories where a person with a troubled past finds new meaning in love.
Another theme is sacrifice. Often, either the alien or the human has to sacrifice something for their relationship. It could be their place in their respective societies or their own safety. In some stories, the male human might have to protect the alien from his own kind who view the alien as a threat.
The theme of sacrifice often appears. In these stories, love can lead to sacrifice. A character in love might sacrifice themselves to stop the spread of the alien virus. They may expose themselves to the virus or take on a dangerous mission to protect their loved ones and the world at large. Also, the fear and uncertainty brought by the alien virus add to the overall tension and drama in the story, making the love story more poignant as it unfolds against this backdrop of disaster.
One common theme is sacrifice. Usually, either the human or the ghost has to sacrifice something for the sake of their love. For example, the human might have to give up their normal life or the ghost might have to sacrifice their chance to move on to the afterlife.
One common theme is the struggle against the impossible. Since a human and a ghost are from different existences, they have to face many difficulties to be together, like the laws of nature and social norms.
Another theme is sacrifice. In a dragon - human love story, either the dragon or the human may have to sacrifice something for the relationship. It could be the dragon giving up its freedom in some way, or the human sacrificing their social standing among their own kind. In some tales, the human might have to leave their family or village to be with the dragon. There's also the theme of discovery. The human discovers the true nature of the dragon, which is not as monstrous as they initially thought, and the dragon discovers the warmth and compassion of humans.
One common theme is sacrifice. The mermaid often has to sacrifice her mermaid life or certain powers to be with the human. Another theme is the idea of two different worlds colliding. Mermaids come from the underwater world which is very different from the human world on land. And of course, there is the theme of true love conquering all, no matter how many difficulties and differences are in the way.
One common theme is the struggle between different natures. The vampire has a dark and often dangerous side due to their need for blood, while the human represents innocence and mortality. This contrast creates a lot of tension in the relationship.