Are they fighting over food or a toy? Or are they just trying to kill each other every time they see one another?? Either way I'm sure it's scary to have two big dogs fighting right in front of you!
I have had aggression problems in my home when a new foster came to live with us, but it was always over a toy or some food. After one serious ear-ripping episode, things settled down because one dog established dominance over the other. If one is willing to back down, things often settle down. It's when both dogs think they are number one that you really have problems. Do you think Raven will submit now?
I'd say stay calm and really analyze the situation, and go with your instinct about whether you think the dogs are really going to seriously hurt one another. Sometimes it just takes a while for two adult dogs to get used to living together. But other times they never get used to it... check out some posts by member Moonlitcroatia . She has two dogs that she has to keep separated constantly.
I sincerely hope things work out for you and you are able to keep both dogs. It is so hard when your babies fight with one another.