You aren't sure when you first notice him, really notice. A shortness of breath, the corners of your lips uncontrollably turning up into a smile, the feeling that you are physically incapable of turning away.
And you know you shouldn't be looking at him like that, because it's a rule of human nature (more ancient and strict than any rule of the House of Black) that one does not fall in love with one's relatives. You're breaking human nature, which can only mean that you yourself are broken, and you are afraid that somehow someone will realize that something inside your head has gone horribly wrong (which is unacceptable, because Blacks are purebloods and purebloods are to be perfect in every respect).
And when you see him again (years and years and an Azkaban sentence later) you are disgusted to find that absolutely nothing has changed, that you may be the Dark Lord's most esteemed servant, that half of the world may fear you, but your heart is betraying you. And when he goes soaring through that curtain, something else in you breaks but you tell yourself it's the only way because with him dead no one will ever discover just how
A/N: Written for the 'I'd never write a story like that' Challenge at the HPFC. (The 'story like that' which I'd never write being incest.) Constructive criticism is always appreciated!
Disclaimer: I don't own the House of Black, the Dark Lord, etc.