One common theme is discovery. Often, the characters discover new summoning spells or techniques that were previously unknown. Another theme is power. The ability to summon can be a very powerful tool, and the fanfictions explore how characters handle this power. For example, they might face the temptation to use it for wrong reasons.
One implication could be a shift in Harry's character. He's typically seen as a hero in the original series, but summoning demons in fanfiction might make him seem more morally ambiguous. It could also introduce a new type of conflict, not just with Voldemort or other dark wizards, but with the forces of the underworld.
Some characters might develop their summoning abilities through intense practice. Just like Harry practiced his Patronus charm, they could spend hours every day trying to perfect the summoning spell, gradually increasing the range and complexity of what they can summon.
In 'harry potter summoning contract fanfiction', the summoning contract can be a source of mystery. Maybe the contract was made generations ago and its true purpose is only gradually revealed. This discovery process can shape the plot as characters search for clues and try to understand the contract's full implications. It could also lead to a race between different characters or groups to either obtain or destroy the contract.
One implication could be a change in his family dynamic. He would no longer be alone in the Dursley's house and would have someone to share his experiences with. This sister could also be a source of emotional support for him.
There are several fanfictions on this topic. In some, Harry uses summoning magic to bring back lost loved ones in a spiritual form to gain advice. For example, in 'Harry's Summoning Quest', he summons the spirits of his parents and Sirius to understand how to defeat Voldemort once and for all. This use of summoning magic adds an emotional depth to the story.
One consequence could be a power imbalance. Naruto is extremely powerful, and his arrival might disrupt the existing power dynamics in the wizarding world. Another consequence could be cultural clash. The ninja way of life is very different from that of wizards. There might also be confusion as to how his abilities work within the magic - based system.
In harry potter summoning spell fanfiction, a common concept is the evolution of the summoning spell. Some stories might have characters modifying the traditional summoning spell to make it more powerful or specific. For instance, instead of just summoning a book, they can summon a particular page within the book. Also, there could be the idea of summoning living creatures in a different way than in the original series. Instead of using the regular animal - summoning spells, a new and more complex spell for summoning mythical or endangered creatures might be created.
Perhaps the contracts having unforeseen consequences. Like the summoner losing a bit of their own magic each time they summon. It adds a layer of risk and drama to the story. In some fanfictions, the summoning contract might be tied to a specific family heirloom, which gives it a historical and mysterious aspect.
One great Harry Potter summoning fanfiction is 'The Summoner's Path'. It has an interesting take on how magic can be used for summoning in the wizarding world. The main character discovers a new way to summon magical creatures and objects, leading to a series of exciting adventures.