He had some gall, this Death Eater. They all did, of course, but this one could take the World Cup in gall - and by more than just a successful Snitch capture. To waltz in here and offer to make his own sister his 'ward' - and dangle pure-blood status on the end as though that nonsense wasn't something they'd fought tooth and nail against - reached a new level of repulsiveness. At that moment it was a very good thing that Selwyn was facing away from James - because he couldn't suppress the expression of intense disgust that crossed his face.
If anything, the rest of it was worse. There were more than enough pure-blood families that had gone a bit funny: just look at how many of them had turned out Death Eaters. And then there were the Blacks - James knew enough about them to appreciate that it was a wonder Sirius had turned out sane. For every happy Weasley (or Potter for that matter - his parents had been more than all right) in the world, there seemed to be two or three from other families who'd had truly rotten childhoods. But Diana had never said ...
"Heard enough?" he asked Diana, as levelly as he was able, still trying to play the part of a relatively disinterested bystander - though it was becoming a struggle. Having Selwyn here changed things: for a start, it scared him. A Death Eater with a personal interest could mean more trouble, and it made getting away all the more important. And brother or no, promises or no, James wouldn't trust a Death eater as far as he could nudge him with his big toe. Reminding Diana of a father who hit her - or cursed her, or did something to her anyway - was clear provocation, and if he pushed her to fight him, who knew how he'd respond? James wanted the bastard gone more than ever.