Just a one shot. It's really short, BUT it was a plot bunny I needed to use.
...
There was an explosion, a huge section of the school being blown away. He had been with her, but now he wasn't. Where was she? He panicked, physically lifting any rubble that he could. His heart skipped a beat when he saw a hand poking out from a pile. No, no, please.
He managed to move the debris, and it was her. He grabbed her forearms, pulling her from the rocks. He collapsed against the other wall, clutching her against his chest. "Dora, please. Please, we have a son." He sobbed. Her neck was broken, bent at an angle he never wanted to see again, and he had no doubts about it. She was dead. His wife was dead.
"Remus?" Harry asked quietly, reaching for the man's shoulder. Remus hadn't moved since the hour of peace, he hadn't even helped in the second half of the battle. He wasn't even sure Remus knew Voldemort was dead. He had just sat, among the row of dead, clutching Tonks' body.
"How could you?" Remus asked, his voice quiet and hoarse. He looked at Harry, his eyes red and exhausted. "How could you, Harry?"
"I didn't do anything." Harry said. Remus gently placed Tonks down, standing in front of Harry.
"This battle was because of you. You returned to Hogwarts, you brought all of us in. If you hadn't come here tonight, she'd be alive. She'd be at home, where she belonged. With our son."
"Remus, I'm sorry for what happened, I didn't want any of this to happen-" Harry began.
Remus stepped forward, glaring at Harry with more rage than he had shown even at Grimmauld. "You killed her. This battle is your fault."
"Remus-" Harry began again. "I didn't want this-"
Harry hadn't been expecting it, but Remus had drawn his wand. Harry felt himself get thrown by a jet of red light, and shocked yells from people who witnessed it. By the time Harry was helped up by Hermione and Ron, Remus was nowhere to be seen.
It would be three years before anyone heard news about Remus again. Harry had gone to Andromeda to find out Remus had left, leaving Teddy with her. He searched for Remus, going as far as Germany to do so. It was when he was in Germany, in Berlin, when he finally found a lead.
And it wasn't good. Remus had died, a year after the battle. Harry felt horrible, he had wanted to talk with Remus, to help him see sense again.
He spent another week, to find his grave. And he issued an apology to a gravestone, hoping that perhaps he'd know. It was another week before he went home, to tell Andromeda.
And it was Andromeda's decision to never tell Teddy the truth. As far as Teddy Lupin was concerned, his parents died together.