The romance of Nymphadora Tonks and Remus Lupin happened, for the most part, off the page. We never witness their first meeting; we never see them slowly but surely falling for one another during Order of the Phoenix missions; nor do we see their eventual wedding — or death.
It was a sub-plot: something happening in the background, a way of showing that the wizarding world doesn't just revolve around Harry Potter, that his story is one of many taking place around him. And it's for this reason that perhaps we never fully absorb the impact of just how sad their romance really is. It’s a love story doomed to fail by prejudice and war, but ends up far worse.
This is the tragedy of Tonks and Lupin.
Remus Lupin was convinced no one could ever love him
In ‘Remus Lupin’, J.K. Rowling details how Lupin and Tonks first met:
Remus, so often melancholy and lonely, was first amused, then impressed, then seriously smitten by the young witch. He had never fallen in love before. If it had happened in peacetime, Remus would have simply taken himself off to a new place and a new job, so that he did not have to endure the pain of watching Tonks fall in love with a handsome, young wizard in the Auror office, which was what he expected to happen.
Pottermore, ‘Remus Lupin’
This was because werewolf Lupin, conditioned by years of stigma and prejudice, considered himself unworthy of love: that he was somehow too damaged for Tonks to ever return his feelings.
But Tonks changed that
Tonks didn't care, though. For over the course of their Order of the Phoenix missions, she too had fallen in love with Lupin — even if he was 'too busy feeling sorry for [himself] to notice’. Lupin, upon finding out, felt happier than he had ever felt in his life. But it didn't last for long.
Their early romance was... complicated
Lupin may have been thrilled to learn of Tonks's feelings but that didn't mean that he immediately reciprocated them. Instead, he shut down. He avoided any further missions with her, barely spoke to her, and started volunteering for the most dangerous tasks.
Tonks believed that he refused to admit his feelings out of nobility. But Lupin was actually in despair, convinced that he could not run the risk of marrying and passing on his lycanthropy to a child. Tonks, convinced that Lupin would never spend time with her again, became desperately unhappy.
But their love for each other was too strong
Again, Tonks didn't care about Lupin's condition. Inspired by Fleur Delacour's love for Bill Weasley — who had been bitten by the same werewolf who attacked Remus as a child, Fenrir Greyback — Tonks made her feelings perfectly clear:
'You see!’ said a strained voice. Tonks was glaring at Lupin. ‘She still wants to marry him, even though he’s been bitten! She doesn’t care!’
‘It’s different,’ said Lupin, barely moving his lips and looking suddenly tense. ‘Bill will not be a full werewolf. The cases are completely —’
‘But I don’t care either, I don’t care!’ said Tonks, seizing the front of Lupin’s robes and shaking them. ‘I’ve told you a million times ...’
Harry Potter and the Half-Blood Prince
Lupin never felt at ease about his love for Tonks, continuing to think that he was being cruel and selfish. Nonetheless, they married quietly in the north of Scotland, with witnesses taken from the local wizarding tavern. As J.K. Rowling writes:
He continued to fear that the stigma attached to him would infect his wife and wished for no fanfare around their union; he swung constantly between elation that he was married to the woman of his dreams and terror of what he might have brought upon them both.
Pottermore, ‘Remus Lupin'
Theirs was a harsh, wartime romance
From the very beginning, the romance of Tonks and Lupin was defined by complications, by challenges to be overcome, by anxiety and fear. For not only did they have to contend with stigma and prejudice, and Lupin's doubts and regrets, but the second wizarding war.
Has such a love ever been tested quite so fiercely? Even when Tonks became pregnant, the news was overshadowed by Lupin's worries. Had he passed his condition on to an innocent child? Had he condemned yet another life to misery? At one point the worry overwhelmed him, and he tried to flee. But in an angry confrontation with Harry, he was convinced to stay.
But then there was hope
Teddy Lupin was born with no signs of lycanthropy, but did inherit his mother's ability to change his appearance at will. The night of his birth was one of the few times when Remus Lupin seemed truly happy. He found the Order and, beaming, told them the good news. With nothing but gratitude, he asked Harry to be Teddy's godfather. There was a toast. ‘To Teddy Remus Lupin,’ said Lupin, ‘a great wizard in the making!’
Everything had worked out. Remus, Nymphadora and Teddy: a family, living happily ever after. Everything was going to be OK.
The Battle of Hogwarts
It's not the despair that gets you. It's the hope.
Yes, after all the struggles, all the worries, all the challenges to overcome, both Nymphadora Tonks and Remus Lupin were killed during the Battle of Hogwarts. It's a cruel end: a final, crushing unfairness in a world of unfairness. Why did it have to be them? Why did it have to be now?
One of the saddest things is that Tonks wasn't supposed to be there at all.
Harry looked at Tonks. ‘I thought you were supposed to be with Teddy at your mother’s?’
‘I couldn’t stand not knowing —’ Tonks looked anguished. ‘She’ll look after him — have you seen Remus?’
‘He was planning to lead a group of fighters into the grounds —’
Without another word, Tonks sped off.
Harry Potter and the Deathly Hallows
We never see Tonks find Lupin. It's uncertain if she even did. The next time Harry sees her she is dead, lying side-by-side with Lupin; together, even in death.
But their legacy lives on
The tragedy of Tonks and Lupin is a sad chapter in a larger story. For their love will live on — through Teddy. And although, much like Harry Potter and his parents, Teddy will grow up not knowing his mother and father, he will understand that it's through their sacrifice, their love, that he grows up in a better world.