What's Greta's Secret?

Our Intel is telling us that the Greta, our big bad, has connected with The Walrus and that a third party is joining the alliance, courtesy of The Walrus too. Whether Greta will be happy to share remains to be seen. She has, so far, been a loner and a top handler, but this missing weapon device appears to be really important to her. I'm interested in finding the reasons behind that. According to my calculations, there is a 77 percent chance that recovering that weapon is the key to Greta's past somehow.