Cass sighed, hating that he had to explain this further, but there was no choice. Not if he wanted to be the one to tell Montague, because no doubt, he'd find out either way.
'Emilia isn't my mother,' he clarified. 'She...helped dad out, when he needed to hide the woman who is my mother from his, my, family. To keep the two of us safe.' Biting his lip, Cass hoped what he was going to say next wouldn't make a difference, though since Montague was a Death Eater he guessed it would.
'My mum is a Muggle, Montague. Dad knew that Grandfather would kill her - and me - if he ever found out. Emilia just agreed to keep his secret, and voila, I all of a sudden had a family worth knowing - and you as a cousin.'
He went silent, waiting for Montague to respond, worrying his lip as he did to keep from talking himself. He didn't like the wait, and no matter how hard he'd tried to prepare himself for this, no matter how much he knew that when he was finished, Montague would likely not want anything to do with him, he still hoped that none of this would matter.