Fantastic Beasts: 10 Potential Harry Potter Spinoffs We'd Rather See

In the books, Regulus Black serves two very simple purposes: to thwart Voldemort by helping to destroy one of his horcruxes, and to provide contrast between Sirius and the rest of his Death Eater family. We know that Regulus joined the cause, and then abandoned Voldemort in a major no-turning-back sort of way that ended up costing him his life.

But this noble act is only dealt with at a very shallow level, and the implications of Regulus's sacrifice are left unexplored. This is a young man who follows the family line to the point of actually becoming a Death Eater, but then something happens somewhere along the way to give him a crisis of faith where he is driven not only to leave Voldemort's service, but to go to extreme length to bring his former boss down.

And then there's the little matter of the dynamic between him and his Gryffindor big brother Sirius, a situation that is barely touched upon in the book, but is immensely fascinating.

As much as people like to think of James and Sirius as brothers, we often forget that Sirius actually had a brother already. And what must that relationship have been like for the both of them?