Friendship and alliances are often themes. When Harry is in a crossover situation, he has to form new friendships and alliances. His Animagus form can sometimes be an advantage in making these connections, as it can make him seem more relatable or trustworthy to certain characters from other universes.
In many of these fanfictions, a major theme is protection. Harry, as a wolf animagus, uses his form to protect those he loves. For example, he might patrol the Hogwarts grounds at night in wolf form to keep students safe from dark creatures. Another theme is identity. Harry has to come to terms with this new part of himself and how it fits into his overall identity as the Boy Who Lived. And sometimes, the fanfictions explore the connection between his wolf form and the ancient magic of the wizarding world, as wolves have often been associated with magic in folklore.
One common theme is the exploration of relationships. Since it's a harem concept, there's a focus on how Harry interacts with multiple characters romantically. Another theme is the power that comes with his Animagus form. It might be used to show his uniqueness or to help him in various situations related to the harem, like protecting them.
One common theme is power. Since a kraken is a very powerful and mythical creature, fanfictions often explore how Harry harnesses this new power. Another theme could be secrecy. Harry would need to keep his kraken form a secret, so stories might revolve around the difficulties of doing so.
Friendship is also a big theme. His friends usually play a role in his journey to becoming a multi animagus. They might help him train or be there to support him when things go wrong. For example, Hermione could use her vast knowledge to assist Harry in understanding the complex magic involved. And Ron could be there for moral support.
A theme that often shows up is secrecy. Since being an Animagus is not something to be taken lightly in the wizarding world, Harry has to keep his panther form a secret. This leads to a lot of tense moments in the fanfictions. Also, friendship is a theme. His friends' reactions to his new form and how they support or sometimes misunderstand him.
One common theme is identity exploration. Harry has to come to terms with this new part of himself as a fox. Another is the use of his fox form for strategic purposes, like sneaking around Hogwarts.
One common theme is self - discovery. Just like in the original series, the female character often discovers more about herself through her animagus form. For example, she might learn about her hidden strengths or fears.
One common theme is self - discovery. Since being a hybrid animagus is something out of the ordinary, the characters often go through a journey of finding out more about themselves and their new abilities.
One common theme is identity. Since being a bear animagus is not a common form, characters often struggle with how this new identity affects their relationships and their place in the wizarding world. Another theme is secrecy. They usually have to keep their animagus form a secret for fear of being misjudged or used.
A common theme is transformation. Since it involves animagus, the physical and emotional transformation of the characters, especially Harry, is often explored. For example, how his new form affects his relationship with Tom.