It felt wrong. It shouldn't have been like that, it shouldn't have been then.
"Finite incantatem," Peter says somberly. Or maybe Regulus is just hearing it somberly. Peter doesn't know, after all, how much is really over.
He feels his skin give way, return to normal. It's still got his tan from Quidditch, yet it feels somehow pale. Or he's just imagining that, too.
He wants to look at it for some ridiculous second, to find out, but he is drawn back to Peter. "That's a useful spell, I think." Peter nods, as if trying to convince himself. "It'd be brilliant for maps, you know, so you'd never fold it up wrong."
Half of Peter's favorite spells would "probably be useful for maps." Regulus had long given up trying to understand that.
"Awesome," he hears himself say. It's never been about being useful, for Regulus.
"Are you okay?" Peter asks, worriedly, "You look worn out."
"I'm fine. Just tired, is all."
Peter nods. "You look so old, with those wrinkles."
"It's okay," Regulus smiles encouragingly. "I do think you've got it down, but if you want to practice again, I'm up for it."
"No, no. Done for the week, I think."
Regulus nods, and it seems to take him an eternity to raise his head back up.
"I've been thinking," Peter says with a forced casualness. "Next time, I think I'd like to try a Warding."
"A—a warding?" Regulus's voice catches, sounding childish, ignorant. "I've got..." Not "my parents" anymore. "I've got Mum," he finishes lamely.
Peter laughs. "Oh, not that sort of a warding. It's what a, a husband would cast on his wife, before...oh, Merlin's beard, not like that!" And they both laugh, blind to everything except the immaturity of the moment.
But Regulus still looks nervous (without reason, he tells himself), and Peter presses on. "You know, so you won't get hurt. Changed the same way others do. I don't want anybody hexing you."
"But what about my own spellcasting? I waited seventeen years to pass up the age ban, I don't want to have to go through you."
"Little prodigy," smiles Peter. "You're...you..." Yet it seems not to be Regulus he's really talking to. "People change," he finally says glancing from side to side as if afraid he's being watched. "They become different, they...I don't want anything to happen to you."
"So you just want me to stay as I am, without changing."
"Right," says Peter, clearly glad that Regulus understands.
Regulus smirks. "You don't need to go to all that trouble. I know a spell that'll do just the thing!"
"Oh?" Regulus isn't sure whether Peter is genuinely curious or disapproving.
"Petrificus Totalus!" His voice sounds more exultant than he had meant it, but his smile turns to shame upon seeing Peter's revulsion. "Fin, finite incantatem," he sputters as Peter climbs up.
"What was that for?" he demands, too shocked to be as angry as he sounds.
"It was a joke," says Regulus, "a joke, I'm sorry."
"Since when have you been throwing off spells left and right?"
"You know what I am. You know what I can do."
"Of course, I didn't mean...I'm sorry, Regulus, I'm just trying to protect you."
"I know you are. But if all you want is for me not to change, for no one to get to me, you might as well kill me right now before I get any older."
"I'd never do that!" But Peter doesn't try very hard to hide the fact that the indignation is faked. Maybe he can't hide it. It's tempting in their mixed-up way.
And Regulus knows that if he had the choice, he'd take it. To die still believing he was enjoying himself with Peter, maybe helping discover something new, and not knowing what had happened until it was far too late, would be better than plunging into another battle for the wrong side. Better than walking to your death and knowing what was coming.
But he didn't have the choice, not really. If he'd cared any less about Kreacher, about what was going on, there wouldn't be enough of him left to enjoy those wasted afternoons. Maybe there hadn't been enough for a long time.
Peter mistook Regulus' wistful silence for a sulked response. "The spells don't hurt too bad, do they?" he asked in a rush.
"No."
Regulus wasn't sure what getting hurt too bad would feel like. He flexed his arm under his robe to remind himself of what had been seared into it; the pain was a message, a sign that he belonged. Peter was a painter and he was the canvas and magic was the brush that bound them together. There was never too much of it.
"Good. You'll tell me, if they do?"
"Yeah." It's an easy promise to make. One he can keep, too, as if it matters.
"Good," Peter says again and smiles. "Thank you. Again. For helping me practice."
"Thank you," says Regulus and means it. "It's nice to get a break from...everything."
Peter nods, his face hardening for a second. He opens his mouth and looks intently curious, but asks merely, "See you next week?"
And this is what aches; the lingering silence as Regulus tries to bring himself, even to say, "There's going to be a battle in a few days, I can't promise anything" or "I might be away". Any sort of lie, just some kind of warning to match the earnestness in Peter's face. But all he can muster is a quiet "yeah."
"Alright," says Peter, Apparating away.
He seems to stare at the space Peter had left behind forever, his mind stalled on that moment, unable to escape.
"Master Regulus?"
The memory is gone.
"I'm fine," says Regulus. "Pour me another."
In the end, he tries to imagine that the Inferius's arms are Peter's, holding him, pulling him somewhere where he will be safe from time.
It doesn't work.
So he remembers what he's done, what Kreacher is taking with him to destroy, and feels an odd burst of emotion. Possibly it's pride.