Grindelwald is granted a wish from Dumbledore due to his good behavior and the remaining power from the binding magic...and since Dumbledore still loves Grindelwald (who is his husband since he never nullified the marriage contract), he grants his wish. But, with a condition. He must complete the ritual with someone else since Dumbledore can not bear the pain of raising a child that will constantly remind him of his love. Sirius Black agrees to perform the ritual since he can not have any children of his own. Grindelwald agrees on 1 condition. Dumbledore MUST allow the child to be trained by both himself and Sirius, and Dumbledore CAN NOT interfere. Dumbledore reluctantly agrees. Now, he must find a suitable mother to bear and raise the child of his husband.

But there is a complication. The ritual drags a soul from another universe to create this new life. This is the story of Heir Grindelwald Black (and through marriage, Dumbledore).

...

Releases whenever I feel like it, nothing regular, just like the rest of my books

Albus Dumbledore: Papa(no bloodline relation)


Harry Potter: Brother/Bro(godson of Sirius so he's still a brother)


Any main teacher at school: Aunt/Auntie or Uncle(Yes, even Severus.  Harry will be different in his eyes here)


Harry will share these titles with Arian since they're brothers.  It's a matter of respect fot the people that will be teaching them magic before Hogwarts. 


Key