A prevalent theme is the discovery of new emotions. Thranduil, being an ancient and somewhat aloof elf - king, discovers new depths of love and passion through his relationship with the reader. The fanfictions also often have the theme of protection. Thranduil wants to protect the reader from the dangers of his world, and the reader may also have a desire to protect Thranduil's heart and his kingdom in some way.
One common theme is the power of love across different species. Since Thranduil is an elf and the reader is presumably a human or from another race, their relationship often explores how love can bridge those gaps. Another theme is adventure. The reader may get involved in Thranduil's world of elves, which is filled with magic and danger, and they go on quests together.
One common theme is the allure of the elven world. Fanfictions often explore the beauty and mystery of Thranduil's realm, with the reader being drawn into it. Another theme is the power dynamic. Thranduil is a king, so there's often a play between his authority and the reader's more ordinary or unique position. Love against odds is also a big theme. Since they come from different worlds or statuses, their relationship has to overcome various obstacles.
A prevalent theme is the exploration of different worlds. The human reader enters the elven realm and has to adapt to its beauty and mystery. There's also the theme of sacrifice. Sometimes the human might sacrifice their own world or future for Thranduil, or vice versa. And of course, there's always the theme of love's power to bridge the gap between two very different beings.
Adventure can also be a theme. The reader could be involved in some sort of adventure in Thranduil's realm, like helping to defend Mirkwood from an enemy. And during this adventure, their relationship with Thranduil develops. It could be that they start as comrades in arms and then gradually fall in love.
Well, in many 'thranduil x reader completed stories', the theme of acceptance is quite prominent. Thranduil has to accept the reader, who may be an outsider in his world, and the reader has to accept Thranduil's elven ways. There's also the theme of loyalty. As the relationship progresses, they show loyalty to each other, especially in times of trouble. And the theme of mystery is there too. Thranduil himself is a rather mysterious character, and the stories often unfold the mystery around him as the reader gets closer to him.
One common theme is the exploration of power. Harry's power as a wizard and Thranduil's as an elven king are often compared and combined in different ways in the stories. Another theme is friendship. Despite their different backgrounds, they form a bond that helps them face challenges.
One common theme is the exploration of different cultures. Thranduil is an elf king and Bilbo is a hobbit, so their cultural differences play a big role. Another theme is the idea of finding love in unexpected places. Their relationship is not something that one would expect in the original Tolkien lore.
One common theme is the 'enemies to lovers' trope. Given that Thranduil and Thorin have had their differences in the original stories, many fanfictions explore how they might overcome those differences and fall in love. Another theme is the exploration of their different cultures. Thranduil is an elf - king and Thorin is a dwarf - prince, so their cultural differences add an interesting layer to the relationship.
One common theme is the clash and then the melding of different cultures. Bilbo is a hobbit from a simple, home - loving society, while Thranduil is an elvenking from a more refined and ancient culture. Another theme is the idea of unexpected friendship or even love that blossoms between two very different individuals.
One common theme is friendship turned into something more. Given their different kingdoms and roles in Middle - earth, their initial interactions might be formal, but in fanfiction, it often evolves into a deeper emotional bond.