МОД: Клинок Армагеддона / Armageddon's Blade

I can't seem to create a nice alpha so that all the pixels are translucent with the right intensity; I'm not an artist -_-

Just copy the fire image and paste it onto the alpha channel. The image will become black and white. And there you have it – a beautiful semi-transparent alpha.
Here, you have harsh edges on the alpha, so part of the black will be visible.

Added 5 minutes later

After that, I created a duplicate layer and applied the Black/White function to it. I copied the resulting layer, created an alpha channel, and pasted it into it.

That's exactly what I was telling you. You didn't even need to make the layer black and white. When you paste an image onto the alpha channel, it automatically becomes black and white.