Here I have the official instructions on how to do the canon of the back for Doom slayer (it sounds interesting to me that all the posts I've done showing this canon have received staff picks). In Pic 1 there is what you need, it can be any color you like or modify it to your liking. There is no need to use glue to keep it in place, so you can easily remove it. I hope you have served this post especially some like Haloguy092 (who would bet he was waiting for this post for his Doom slayer).