In the beginning of the novel, it is the snowball thrown by Dargelos that plunges Paul deep into the fantasy world of the Game and the confines of the Room, both of which are manipulated in ways both physically real and apparently supernatural by his older sister. It is Dargelos, or rather Paul's attraction for that ideal, that gives Elisabeth the power she needs to keep Paul in her grasp. For Elisabeth, the fatal snowball is one of her miracles, as is the mysterious "poison", both gifts from Dargelos that draw Paul further into the Room and in the case of the latter gift, permanently. "She invested the poison with symbolic properties: it was the antidote to pettiness and parochialism; would, must-surely-lead to the final overthrow of Agatha" (164).
We know that Elisabeth is physically attracted to her brother (not necessarily the other way around). She is "melted, almost to tears, by the grace and beauty of his body" (36). I think that attraction as well as her fear of being left alone fuels her desire to possess him completely. On page 42, she attempts to get him to play the Game by submitting to being hypnotized by her. At this point in the story, it just sounds like an innocent child's game. I see a parallel here with her Shakesperean scheme that takes place later in the novel in regards to the letter. As she wanders through the mansion like a vampire or a spider (I think the text refers to her a few times as both) manipulating the others, she encounters zero resistance from any of them. Although it isn't explicitly stated, the absolutely ridiculous ease with which she succeeds suggests to me that she has literally hypnotized the other three enfants. Perhaps the Room interacts with the real world through Elisabeth and the Game. Paul, at this point, seems detached from all three due to his feelings for Agatha (whether or not they are genuine) and has just as little power as both Agatha and Gerard themselves. Elisabeth senses Paul's premier design for Agatha, subjecting her to his will (something he could have never done to Dargelos), and calls this "cheating" (94). Why? Is it because the physical resemblance of Agatha to Dargelos-Athelie threatens to upset Paul's fixation on the Dargelos already contained in the Room, the Dargelos in the photgraph and in Paul's various clippings?
In the end, it is Elisabeth and the Room that win. The final miracle, the "poison", leads to their deaths, but it also rejoins Paul and Elisabeth in the Room, "where incest lurks no more" (181). Paul is referred, I believe on the same page, as Elisabeth's prey. Agatha calls out to Paul as a way of pulling him back, but he is already gone and "to disturb a player once this third stage had been accomplished was considered unforgivable" (34). Agatha is finally abandoned by the Room, overthrown by Elisabeth.
This book, from beginning to end, reminded me so much of the movie Sunset Boulevard... both have to deal with a vampire or spider-like femme fatale that ensnares a man in her seedy fantasy world and go mad(der) in the process of trying to possess him completely, destroying them both. The fictional Norma Desmond, no doubt one of my favorite Hollywood personnages of all time, is a real piece of work. Even though Elisabeth shoots herself at the end of this book, I think the book ends on a happier note than that movie. I'm interested to see what sort of mood the ending of the film version of Les Enfants Terribles has.
Oh, and even though Cocteau approached the director to do the film and worked with him on it, I don't think they were able to agree on much... and the final product did not please Cocteau at all. I think I read that somewhere. Interesting to know for those interested in comparing the book to the film.