Weight of a Legacy

Arcturus Black is most likely the last member of an ancient family. Something inexplicable happens to every member of House Black, whether it's magic or trauma, and it causes everyone to go mad.
That might be the fate of a family that sided with dark wizards for centuries, but that can't be it.
Arcturus watched firsthand as his grandmother succumbs to the ever-growing madness.
It was only a harmless comment, but it got Arcturus thinking. What if his family was cursed?
In other words, Arcturus is convinced his family is cursed. His grandmother is lost in her mind, and his uncle, on the run, refuses to talk to him. With his sixth year in full swing, he can't possibly focus on his studies because if the family is cursed, then there has to be a way to break it. Right?