His second rendition of the potion had several major improvements because he had far more ingredients available to him. He borrowed Hermione's cauldron and scales because the ones stored in the house hadn't been cleaned after whomever had last used them and he didn't trust whatever potion had had decades to mature on their surfaces.

Of course, she then insisted on being allowed to help and he only made a superficial effort to convince her otherwise.

So they occupied the spacious brewing cellar of the order of the phoenix head quarters and spent several days cleaning the place up, chucking out unlabelled potions and mouldy ingredients. Almost every piece of potion making equipment was dirty and had to be disposed of which left the room very bare by the time they were done.

They picked the cleanest brewing stand and set up Hermione's cauldron over it, then borrowed a knife and chopping board from the kitchen. Hermione laid out their ingredients meticulously as Gellert drew the instructions onto the wall where she could see them easily from everywhere. He double checked that everything was ready, then began.

He prodded the fire to life underneath the cauldron with his wand as Hermione finely chopped dittany leaves. He filled it with water and added the bones – beef this time. He stirred it anticlockwise as Hermione poured in her dittany with a smile up at him. This time it went a light lilac as he added Albus's hair. Hermione winced as he added a living spider which fizzled slightly as it hit the softly boiling surface. He recited the incantation and waved his wand as Hermione handed him the fragments of stone. He drew his wand across his already scarred palm and coated the stones in blood before dropping them into the cauldron. Flames licked across the surface and it steamed thickly as he carefully measured it into a cup. He would only need a small amount this time as he only needed to reduce his age by a couple of years.

Hermione handed the cup to him with a nervous smile and he returned her expression, holding it up in a toast. Then he downed it in one. It burned less than last time, which was an improvement but it really could have done with more dittany.

That was his last thought before he lost consciousness.

The world was bright when he came too; he blinked several times, puzzled by the change. It was almost like he'd lost a colour but couldn't remember what that colour had looked like to see where it was missing. It was just a feeling of absence.

'Gellert! Are you okay?' That was Hermione's voice, so at least he hadn't turned the whole room into a crisp this time.

'Hermione?' He almost expected his voice to be hoarse, but it was smooth. He must have screamed less than the last time.

'It worked, you're our age now.' He heard her pouring a glass of water and he pushed himself up, realising that he was on a soft bed in the headquarters. It was decked out in green and gold with most of the furniture missing, which he assumed meant that it had been hastily cleaned for him to occupy.

She pushed the glass into his hand and he took it gratefully, draining it without taking a breath. She poured him a second glass and he drank that one slower, finally taking the time to assess his new form. First task was to check his magic – he flexed his hand and blue flames flared along his fingers. Hermione gasped in awe as he let it drip off each finger, testing the limits of his magic. Then he focused on the aesthetics, relieved to find that his hair was still intact. In fact, even his clothing was unharmed, so he must have managed to tame the flames by adding dittany.

'How do I look?' He asked curiously, noticing that all but one of the scars on his hands had healed. He'd also lost his empowerment rune, which he'd have to recast before school began. He would also need to redo the necromancer's rite just in case he needed to raise any dead, but that was a ritual that he'd need to travel for; England was far too regulated to get away with that. The bond with Albus was still intact, as was the loyalty of the elder wand.

'Handsome.' She replied, then blushed as she realised what she'd said. He laughed, moving to stand and she leapt to his side to help him up. He would have snapped that he was not an invalid but he knew it was meant to be a kind action rather than an insult.

She handed him his wand and he gratefully holstered it, then wished he hadn't when Molly Weasley arrived. Her face turned thunderous when she saw him up, her face softened momentarily as she looked at Hermione and she gently asked the young witch if she could have a moment with him. He nudged Hermione's shoulder to get her to obey the matron and she reluctantly obeyed.

Mrs. Weasley managed to restrain herself until the door closed before erupting into furious screeching.

'What were you thinking! Dragging that young girl into some horrific ritual, Albus Dumbledore trusted you. She was worried sick, terrified that she'd killed you and you were too busy being concerned about your own immortality to consider the damage to her soul.'

Gellert waited her out calmly, eventually she would have to pause to take a breath and then he could tell her the full story. She paused briefly and he interrupted her.

'Actually, Albus instructed me to make the potion.' He said breezily and Molly Weasley froze with her mouth open. 'There is nothing soul damaging about cutting ingredients, Hermione will be fine. My soul is so far gone already that the effects will be negligible and Albus needs someone to protect Harry Potter in school.'

For a moment she just stared at him, completely speechless. It did sound very heroic, he realised with a sinking feeling; sacrificing his own soul so that he could keep a student safe. Of course, if one was unfamiliar with the dark arts they would think that. He hadn't even considered the impact on his soul, not since the first time he'd torn it when he killed his father as a teenager. It had hurt less every time after that and eventually he'd just stopped paying attention.

'Is there anything I can do for you? Chicken soup?' Molly's ability to change from banshee to mother was awe inspiring.

'I'll need to visit Gringotts, then I need to go away for a couple of days.' He told her, tying up the shoes that someone – probably Hermione had left neatly at his bedside.

'Anything I can help with dear?' Molly asked and he shook his head.

'Just furthering my own interests.' He told her with a wry grin as he brushed past her out of the door.