Sirius's office was not yet an office in any meaningful sense. There was a desk because there had always been a desk in this room, left behind by whoever had last inhabited the castle before the centuries emptied it out, and there were two chairs that Sirius had conjured himself and had not yet decided if he like it. The walls were bare stone. There was a window that looked out over the North Sea and did that job extremely well, which was currently its only contribution to the space.
He had plans for it. Vague ones, the kind that existed more as intention than detail. He had been thinking about what came after the Custodians. The Black vaults under Sirius' name are enough to support his family for generations comfortably without even needing himself to lift a finger but because Sirius without a purpose is a special kind of problem. Sirius knows that. Without something to do outside of family, he will be one reckless idiot. He has a wife and four children to think about. Sirius even didn't tell Esme about his motorcycle yet. She'll probably end his life if she found him driving around it at the highlands with the children in tow.
He could stay with the Custodians. But he can't. Staying with them means he must be away for months and sometimes years at a time and he can't exactly bring Esme and the children with him. That was why he plans to resign.
Isaac was standing by the window with his arms crossed, looking at him patiently for a reasonable amount of time and had now decided the reasonable amount of time was over.
"Ask," Sirius said.
"The hound," Isaac said.
Sirius exhaled. He had known that was coming first. Isaac was a man who organized his questions in order of what he understood least, and the hound was currently at the top of that list by a considerable distance.
"I don't have a clean explanation for it," Sirius said. "What I can tell you is that it wasn't something I did consciously. It wasn't a spell, wasn't an incantation. It came from something else." He paused, trying to find the right words for something that had no established vocabulary. "There was a ritual. Before the children. Something happened during it that changed things. I met — something. An entity. It told me that ancient magic had been reawakened and that I had been marked by it, that I would have to earn my way to understanding it rather than being shown." He looked at Isaac. "What happened in that cave. I felt it. The same feeling I had when I was in that place. The whisps were already there when we entered. The place had residue in it — old magic, the kind that doesn't come from wands. I think the hound was a product of that."
Isaac was quiet for a moment, processing in the way he processed — completely, without visible reaction, filing everything before he responded. "Ancient magic," he said finally. "The ICW has records of it. Old ones. Most of our ancient locations, Hogwarts included are filled with it, but nobody really understood it nor know how to use it. Some say it's a myth at this point."
"It isn't a myth."
"No," Isaac said, without surprise. "I didn't think it was." He uncrossed his arms and turned from the window.
"The ICW has had an open file on Voldemort since before the war ended. We were never permitted to intervene. Dumbledore made sure of that, and enough ministries deferred to him that our hands were tied even as the damage spread across half of Europe. It was a political failure of the first order and several people in our organization are still furious about it." His hazel eyes settled on Sirius steadily. "Having access to two brothers from opposite sides of that war — one who fought against him from the inside, one who fought against him from the outside — is something the ICW would consider significant."
"I know," Sirius said. "I'll keep you informed about Regulus. What he knows, what he's willing to share, when he's well enough to share it. But on my terms and his. Not the ICW's timeline."
Isaac nodded once. "Understood." He paused. "He went into that cave to destroy something. Something Voldemort created. I won't ask what it was tonight, but I'll want to know eventually."
"Eventually," Sirius agreed.
The word sat between them for a moment, comfortable in the way that words between people who trust each other can be comfortable even when they're carrying weight.
"The children," Isaac said.
Sirius looked at him.
"What happened in that vault," Isaac said, "what we helped you find when you were still with us, what we saw in that cave — none of it leaves this team. You have my word, and my word covers all of them. They would take it to their graves. Under torture if it came to it." He said it the way he said everything important — plainly, without ceremony, as a fact rather than a promise. "You don't need to worry about that, Sirius."
Something in Sirius's chest that had been quietly braced released. He had trusted them. He had known, in the way you know things about people you have worked beside in dangerous places, that they would hold it. But hearing it said was different from knowing it.
"Thank you," he said. It came out simpler than he intended and more honest because of it.
Isaac's mouth curved slightly. "Don't thank me. Just keep us informed about the ancient magic situation. If what you're carrying is what I think it is, the ICW is going to want to understand it at some point whether you like it or not. Better it comes through you than around you."
"Always the strategist," Sirius said.
"One of us has to be." Isaac moved toward the door, then stopped. "For what it's worth. You were one of the best we had. As much as I don't want you to resign. I understood why. Staying with us means you must stay away from Esme and the children for months or even years. Children do need the presence of their father. But the seat stays open. Whatever you need, whenever you need it. Honestly, I placed you in reserved just in case."
"Just in case?"
"You never know."
"You never turn off do you."
"That's why I'm the major."
*****
Blacktide has many sitting rooms. The one in the family wing is reserve for family only but with this many people, Sirius and Esme has to create a space big enough to host such people.
Sirius heard it before he entered the sitting room. Edu's laugh, which had its own weather system, and underneath it the higher sounds of children who had decided that a group of battle-hardened international wizards were an acceptable substitute for playground equipment.
He stopped in the doorway.
Esme was across the room with Bastien and the other healers, sitting with the ease of someone who had finally put down something heavy. She looked up when he entered and gave him a smile before returning to the conversation.
He recalled arriving back at Blacktide still covered in the filth of the cave, his boots leaving dark water stains on the stone floor. He hadn't even reached the second step before Esme crossed the entrance hall and pulled him in without a word. He'd tried to protest — he was soaking wet and smelled like cave water and things he didn't want to name — and she'd said something very quiet and very French against his shoulder that he hadn't quite caught but understood perfectly. She didn't let go for a long time.
He hadn't fully understood until then how worried she had been. It wasn't something Esme wore openly. But he felt it in the grip of her hands and the way her breathing steadied against him, and something about being held like that — like someone had needed him to come back specifically — had loosened something in his chest he hadn't known was tight.
Sirius then looked at his children.
Rigel and Corvus had apparently decided that Edu was a perfectly reasonable climbing structure and Edu had apparently agreed, one boy on each shoulder, his enormous laugh shaking them both as he walked circles around the room. Corvus had both hands fisted in Edu's hair for balance and was grinning with the uninhibited brightness of a boy who had not yet learned to ration his joy, and Sirius felt something clench in his chest at the sight of it — at how much that smile had cost, and how freely it was being spent now.
Rigel on the other shoulder was laughing too, quieter than his brother, the way he did everything — taking it in as much as expressing it, those blue-green eyes bright and present and missing nothing. He caught Sirius's eye across the room and the laugh stayed but something in his expression shifted into the look he had, the one that was already too old for his face and probably always would be.
Sirius held his gaze for a moment and nodded, just once.
Rigel nodded back.
In the corner of the room, one of the Custodians — Henrique, a broad-shouldered Portuguese wizard who had once faced down a dragon with nothing but a shield charm and what he described as an unreasonable amount of confidence — was crouching down to Alphard's level with his arms open and his expression hopeful.
"Hug?" he offered.
Alphard regarded him with the gravity of a two-year-old who has developed strong opinions about people.
"Ugly," Alphard said.
Henrique's face fell with a completeness that was almost artistic.
Sirius pressed his lips together very firmly trying not to laugh. So, Alphard moved on from this favorite word "no" and found a new one. Where he learned ugly, Sirius doesn't know yet.
Across the room, Mara was sitting with her back against the wall and Lyra installed beside her with the settled quality of someone who had selected their preferred location and intended to remain there.
Mara's hands were moving through Lyra's straight blonde hair in slow, methodical sections, braiding with the same quiet efficiency she brought to everything. Lyra was watching the room with her usual expression of calm, comprehensive assessment, occasionally making observations to Mara in a low voice that Sirius couldn't hear from the doorway.
Mara responded to each one with a single word or a nod.
Isaac appeared at his shoulder, looked at the room for a moment, and then his gaze found the far corner where Wyatt Vance was leaning against the wall next to Bastien with the practiced ease of a man who considered any vertical surface a reasonable place to make himself comfortable. Bastien had a cup of something warm that he was holding with both hands and studying with great concentration. His ears were pink.
"I need to rescue that poor boy," Isaac said, with the resignation of a man who had said this before and expected to say it again. "That man never learns."
He moved off into the room with the purposeful stride of someone who had decided that intervention was necessary and had already planned the approach.
Sirius stayed in the doorway.
He watched Edu laugh. He watched Corvus grin and Rigel observe, and Alphard pass devastating judgment on Henrique, who was now sitting on the floor looking at his hands with the expression of a man questioning his choices. He watched Lyra say something to Mara that made Mara's mouth do the thing that was almost a smile.
He thought about the cave. About the water and the dark and the weight of his brother in his arms. About the hound blazing white in the dark.
He thought about Regulus upstairs, breathing properly now, sleeping the sleep of someone who had finally been allowed to stop holding on.
He thought about Esme's exhale against his shoulder when she hugged him.
For the first time in longer than he could remember Sirius Black felt, quietly and completely, that everything was exactly as it should be.