Today’s second glitch:
Y’know, shoes are for wearing. Unless there’s something else the character is supposed to do with the shoes to make them perform their magic, there’s no need to say they give him this ability only if he wears them.
He had a very special pair of shoes that permitted him to walk in another universe.
If you really, really want to keep the original wording intact for some strange reason (maybe polishing the shoes causes a different magical effect from wearing them, and you want to make the distinction), this is how to punctuate it: He had a very special pair of shoes, ones that, if he wore them, permitted him to walk in another universe.