The bit about 'cold fire' rings a faint bell. I'm going to have a look in the library at Grimmauld Place and see if anything turns up.

Hasn't Alecto had nosebleeds? I'm trying to remember what Poppy said about her illness the other day.

Unfortunately, forcing Terry to hurt someone else sounds like exactly the sort of sadistic game that Amycus would relish for its own sake. That could have been part of the ritual, or it could have been entirely for fun.