How can toy series be incorporated into Harry Potter fanfic effectively?

Parody is another effective method. You can create a story that parodies the typical 'Harry Potter' plot. For example, instead of Voldemort being the big bad villain, it's a wizard who's obsessed with making everyone wear matching socks. The absurdity of such a change can be really funny. And when the heroes like Harry and his friends have to deal with this strange new 'threat', it can lead to all kinds of humorous situations.

Humor can be added through character quirks. Like Neville's clumsiness can be exaggerated in a funny way. For instance, he could accidentally trip over his own plant while trying to show it off in Herbology class. Also, using puns related to magic. For example, when someone says 'I'm so charmed, it must be the spell of good humor!'

You could make the succubus drain be part of a curse that was placed on Hogwarts long ago. Maybe it was put there by a dark wizard who wanted to weaken the school's magic. In the fanfic, the characters start noticing that students are getting weaker and tired all the time. They then discover the source is a succubus draining their energy, and they have to search through old books and magic spells to find a way to break the curse.

One way is to create a new Ministry department that deals with magical taxes. You could write about how this department audits wizarding businesses. For example, Ollivander's wand shop might be audited for taxes on the sales of wands. Another way is to introduce a tax on magical creatures. Hagrid might have to deal with the new tax regulations for his care of magical creatures at Hogwarts.

Well, 'Harry Potter' candy can be used as a plot device in fanfics. For instance, a poisoned candy could be sent to a character, leading to a mystery of who the culprit is. It could also be a way to show friendship, like when a character gives their favorite Honeydukes candy to another as a sign of loyalty.

The defenestration spell could be incorporated as a key plot device. For instance, if there's a mystery about a series of 'window - related' incidents in Hogwarts, and Harry suspects the defenestration spell is involved. He then starts to investigate who might be using it and for what purpose.

It could be a reference to a certain character's look or attitude. Maybe there's a new character in the fanfic who has a steely gaze, and the author describes it as 'blue steel' to give a sense of mystery and cold determination. This character could be an ally or an enemy to Harry and his friends, adding a new layer of intrigue to the story.

They can be incorporated as new magical creatures in the Forbidden Forest. Maybe they have their own hidden enclaves there and interact with Hogwarts students who stumble upon them. For instance, a faery hero could offer help to a lost student by using its faery magic to guide them back to the castle.

It could be a magical place that characters from both universes are drawn to. For example, Frodo from 'The Hobbit' might be lured to 'Over the Rainbow' by a strange magic, and there he meets Harry Potter. They then have to work together to return to their respective worlds.

One way is to have it as a guide. For instance, a young wizard or witch could be lost in a forest near Hogwarts, and a blackbird flying overhead could lead them to safety, like to a hidden passage or an old, forgotten hut that holds some important magical item.