She could be heartbroken. Tonks is a passionate character. She may initially be in denial, not wanting to believe that Lupin would leave her. She might try to talk to him, convince him that they can overcome any difficulties together.
It could lead to a whole new dynamic in the wizarding world. Maybe they'd have more adventures together and play a greater role in protecting it.
There are also authors who are really good at character development in their fanfictions. Take 'TonksTales' for example. They create stories where Lupin and Tonks' characters are very true to the original books but also have new and interesting facets added. They might explore Lupin's insecurities in a new light or show Tonks' Metamorphmagus abilities in unique situations. Another great author could be 'RemusAndNymphadora' who writes stories that are often set in different time periods of the 'Harry Potter' world related to Lupin and Tonks.
One interesting fanfiction could be about Tonks and Lupin's relationship during the early days of their acquaintance at the Order of the Phoenix. It might explore how they first noticed each other's unique qualities, like Tonks' Metamorphmagus abilities catching Lupin's attention.
One interesting fanfiction could be about Lupin and Tonks' relationship during the final battle. It might show how they supported each other and fought side by side. Another could be a pre - story of how they first met, perhaps at the Order of the Phoenix headquarters, with Tonks being all clumsy around Lupin which is really cute. There could also be a fanfiction where after Lupin's death, Tonks in a magical way gets to communicate with him one last time to say goodbye properly.
One possible reason could be his self - loathing due to his werewolf condition. He might think he's not good enough for Tonks and that she'd be better off without him, fearing that his lycanthropy could bring danger or a difficult life to her.
You can start by looking on fanfiction websites like Archive of Our Own (AO3). It has a large collection of 'Harry Potter' fanfictions, and you can specifically search for ones related to Tonks and Lupin. Just type in their names in the search bar and you'll get a bunch of options.
The teachers at Hogwarts would have different reactions. McGonagall might be disappointed in Hermione's choice, seeing it as a disruption to the harmony of the school. She might also be concerned about the potential for drama and distraction. Dumbledore, on the other hand, would be more understanding. He would likely see it as a complex emotional situation and might try to guide Hermione through it. Snape himself would be in a very difficult position. He's not used to this kind of attention and might initially reject Hermione's feelings out of self - preservation and his own past traumas.
One great Lupin and Tonks fanfiction is 'The Lupin - Tonks Story' on FanFiction.net. It really delves into their relationship, from their initial meetings to the deeper emotional bonds. The writer captures Tonks' free - spirited nature and Lupin's more reserved personality very well, making their interactions seem natural.
Hermione would be heartbroken as well. She would likely try to find a way to bring Lupin back, delving deep into the library's restricted section for any possible spells or solutions. She would also be the one to comfort Harry and Ron, using her logic to try to make sense of the senseless loss.
In many lupin tonks fanfictions, the theme of sacrifice is present. Lupin may sacrifice his own happiness for Tonks' safety or vice versa. Another common theme is the idea of redemption. Lupin, with his werewolf nature which is often seen as a 'flaw', finds redemption through Tonks' love. Also, the theme of friendship within their relationship is important. Their friends play a role in either supporting or challenging their relationship, which is often explored in these fanfictions.