Forum: Lost Stories

I read a story a little while ago in which the world was invaded by aliens through a portal and used magic to kill humans. They only sent one or two aliens at a time and one boy was able to kill one of the aliens and steal his power, enslaving another alien along the way. Can anyone help me?

This has been asked before and not that long ago, look at https://storiesonline.net/s/47245/the-power-and-the-price by Fick Suck.

Thanks . This is the story I was looking for