Common themes in Celtic Fae adult stories include the concept of fate. The Fae are sometimes seen as agents of fate, guiding or interfering with the destinies of humans. There's also the theme of transformation. The Fae can transform themselves or transform the humans they interact with, which can lead to all sorts of strange and interesting situations. And of course, the theme of the Otherworld, a place that is both beautiful and dangerous, and is often central to these stories.
I would recommend 'The Black Dog of the Fae' which is a lesser - known but very interesting Celtic Fae story. It has elements of horror and mystery. 'The Fae's Gift' is also a good one. It focuses on a human receiving a gift from the Fae and the unforeseen events that unfold. Also, 'The Lady of the Lake', which has strong Fae elements in the Celtic context, is worth reading.
Death is a very common theme. Many Celtic ghost stories involve spirits that are related to death, like the banshee that warns of impending death. Another common theme is the idea of the otherworld. Ghosts often seem to belong to a different realm and sometimes cross over into the human world. For example, the shape - shifting Pooka can move between different states of existence.
Isolation is another theme. Many of these stories take place in remote areas, away from the safety of the village or town. For instance, a person might be alone in the forest and encounter a terrifying creature. This isolation heightens the sense of fear as there is no immediate help available. It also makes the characters more vulnerable to the supernatural forces that lurk in these lonely places.
Fate is a common theme. In many stories like Tristan and Isolde, their love was not of their own choosing at first due to the love potion, but fate intertwined their lives in a complex way. Another theme is the conflict with social norms. Couples often faced difficulties because their love went against the arranged marriages or the will of the rulers.
Magic is a very common theme. Many Celtic bedtime stories involve magical creatures like fairies, selkies, and giants. For example, the stories of fairies often show their magical powers to grant wishes or play tricks on humans.
Magic is a very common theme. For example, in many stories there are magical creatures like fairies or druids with special powers.
One common theme is identity. Hermione has to figure out who she is now as a fae, different from her identity as a witch. For example, in many stories, she has to learn new fae magic which makes her question her place in both the wizarding and fae worlds.
One common theme is the clash between the human and fae worlds. The differences in their cultures, values, and ways of life often create conflicts and tensions in the relationships. Another theme is the magic that surrounds the fae. This magic can be both alluring and dangerous, and it often plays a role in the development of the romance.
One common theme is identity. Harry has to figure out who he is as a fae in addition to being a wizard. Another is power. Fae often have different types of powers, and the fanfictions usually explore how Harry's new powers interact with his existing wizarding abilities.
One common theme is identity. Bella has to figure out who she is as a fae, different from her human self. Another is magic. The fanfictions usually explore the different types of fae magic and how Bella uses or discovers it.