It's inescapable! Painful knowledge coming from deep within your shattered heart. How could it come to this? Of all the things you might have expected to see, this was the last. It might well be the last thing you ever see, his eyes looking into yours as one of you dies.
It's alway a means to an end. A way to make things right. Maybe it's just the road to Hell because it's paved with good intentions. The end can't always justify the means, the sacrifice, the sheer gall to always think that only the goal he percieves matters.
Don't the three of you matter at all? Years you have looked and listened and waited, and this is what you find at the end of it all? Things so broken that no amount of caring can glue it back together.
There was at least a litte hope until you saw that thing on his arm. You know that it will destroy you all. Brother will be pitted against brother as it was the first time. As it has always been. And you won't stand aside but in between. Even when you reach the end of this final mistake. You can't, won't let him go to that dark abyss after having destroyed his only family, his brother.
So, call your followers and give your instruction. They think you will lead them to victory. You can't let them see the truth, eventually they must learn to live without following. Find it in themselves to know what to do.
Only you know that you'll never see the end of their struggle, because your death will be the only thing standing between his soul and the pit. Always willing to bleed for the Winchesters, always willing to die for the brothers that need each other even more than they know.