A Mother's Love
"Do you, Regulus Arcturus Black, swear upon your noble and most ancient blood that you will not dishonour our family's name as your brother has done?" mother asked, her wand pressed deeply into Regulus' wrist, right under the mangled scar which was all that remained of the oath he had sworn to Sirius.
"I swear, so mote it be," Regulus vowed, and sucked in a sharp breath as the brand seared into his skin. The pain was vicious, much worse than the stinging which the oath he had sworn to Sirius had caused all those years ago, but he tried not to think about that; much the same way he avoided thinking about anything related to Sirius, really.
He simply bit his lower lip and ducked his head, leaving the room as fast as was acceptable while clutching his wrist. Once he was out of mother’s earshot, he retreated to a bathroom and turned on the cold water, dunking his inflamed wrist under it.
The initial burn of the icy cold against the searing burn on his wrist elicited a harsh hiss of pain from him, but his discomfort quickly subsided as the cold water did its job. Distantly, he thought that Sirius probably would have known a spell for this type of thing, but that was neither here nor there.
Whatever they had once shared, it had wilted long before the brand had split open, probably around about the time Regulus was sorted into Slytherin.
Regulus let out a deep, breathy sigh. No matter how much he did not want to admit it, he missed Sirius. His brand began prickling angrily at the thought, and he rushed to soothe it once again, but the thought did not become any less true simply because it had left the forefront of his mind.
-oathbreaker-
As Regulus discreetly slipped ‘Secrets of the Darkest Art’ off of its shelf and into the satchel around his shoulder, he felt a burning sensation on his wrist. Figuring it was simply his Dark Mark agitating his skin, he paid it no mind, and made his way up to his room, cracking the book open and scouring it for information.
As he came to the conclusion that the only thing which the locket Kreacher had been forced to hide could have been was a horcrux, and that he would have to destroy it, the brand for the oath he had sworn to his mother split open.
He shoved his fist into his mouth and bit down hard to stifle the shriek which would have otherwise left him, and fell off of his seat to the floor, racked with a searing pain which was so, so much worse than it had been when Sirius ran away. It felt he had plunged his entire hand into molten hot iron, and he writhed terribly as the pain washed over him in waves.
After almost ten minutes had passed, Regulus finally removed his fist from his mouth, and dared to survey the damage. His right hand was bleeding, with teeth marks clearly visible in his pasty white flesh, while his left was completely soaked in blood, the faded scar from Sirius’ brand running anew as the freshly opened cut below it continued to sting.
With gritted teeth, he grasped his wand and began uttering countercurses, slowly threading the skin back together. When he was done, his wrist was left in a bigger mess than it ever had been, with a dreadfully uneven ridge of scar tissue taking the place of the wide gash which had been there prior.
With a shuddering breath, Regulus pulled up his sleeve as far as it would go, covering up the evidence of what was now his second broken oath.
Despite what they might insist, Sirius and mother now finally had something in common - both had left Regulus with a permanent scar.
A mother’s love really was a fickle thing.