One possible theme could be friendship. Maybe the angry unicorn initially has a conflict with Balto but then they become friends.
Another theme could be the power of forgiveness. The angry unicorn could have done something wrong or been wronged in the past, and throughout the fanfic, the characters in the Balto world could teach it about forgiveness. This would add an emotional depth to the story as the unicorn has to come to terms with its anger and let go of grudges.
I'm not sure of a specific 'angryunicorn balto fanfic' off the top of my head. You could try searching on fanfic websites like Archive of Our Own or Fanfiction.net.
A possible crossover could be that Balto is a form of Animagus. In the 'Harry Potter' universe, some wizards can transform into animals. Balto could be an Animagus who was born in the wizarding world but got lost in the Muggle world. When he returns, he has to adapt to the wizarding ways again.
One common theme could be friendship. Balto and Steele have a complex relationship in the original story, and fanfics might explore different aspects of their friendship, whether it's mending a broken bond or strengthening an existing one.
One common theme is friendship. Since they are both characters from the same universe, many fanfics explore how they form a bond and rely on each other.
Friendship and loyalty are also popular themes. Balto and Jenna's relationship in the original story has elements of friendship, and fanfic writers may expand on that. They could write about how they support each other through difficult times and how their loyalty to one another is unwavering.
Friendship could be a major theme. Characters from two different worlds, like Balto and Scrat from Ice Age, could form an unlikely friendship. Despite their differences in species and the worlds they come from, they find common ground and support each other.
One main theme is rivalry. Balto and Steele are often at odds in the original story, and this continues in many fanfics. Another theme is redemption, especially for Steele as he tries to prove himself in a different light. And friendship is also a theme, as they slowly move from enemies to something more.
Redemption could also be a theme. If Christian Knight has some sort of past misdeeds or a troubled backstory, fanfics might explore his journey of redemption with the help and influence of Balto. They could also face moral dilemmas together, which adds depth to the story and the characters' development.
The theme of loyalty is quite prevalent. Balto is known for his loyalty in the original story, and in fanfics, this loyalty extends to his love. He will fight against all odds in the action scenes to stay loyal to his beloved. And the theme of growth is also there. Through the action and the romance, Balto and the other characters grow, becoming stronger and more in tune with their emotions.
Another theme is the power of love in the face of adversity. In 'balto action romance fanfic', the love between the characters gives them the strength to overcome all kinds of difficulties, like fighting off predators or surviving in a harsh environment. It shows that love can be a motivating force even in an action - filled story.