I downloaded your file, and here are a couple of the changes I made that made the glow work correctly:
From left to right, here’s how it goes:
You should be using the image itself for the glow, not the AO pass. Since the blade is emissive, it shouldn’t have shadows. Fading glow towards the edges can be done in different ways, and the rest of the chain needs the linear values of the blade to generate a proper glow.
The multiply node should not be clamping values. The scene linear values will be needed later for the proper glow, and clamping gets rid of those values.
You can still use relative for the blur if you like, but I was using non-relative, so if you’re copying you’ll need this. Otherwise, the value should just be small, since the only purpose of this blur is to soften the edge a bit.
To do all of this correctly though a reference for what you’re going for would be helpful. Right now, it’s mostly a shot in the dark since you haven’t clearly indicated what you want as a result. If you want a more realistic look, this is a good direction to go. If you want more of an EP III look, that will require a different approach. Hopefully some of this will help you learn the tools so you can achieve anything you want.