Someone had the フェイ tag as one of Fei Rune's other names, when that's a generic "Fey/Faye/Fei" that could apply to dozens of characters, and doesn't point to any one particular character on Pixiv. In this case, it was actually intended for the redhead girl named Fey, who has no other name to go by. Unfortunately, the parser doesn't know any better, and tagged Fei Rune on this image, because someone told it that's what フェイ means.

Don't do this. If you see a tag pointing to more than one character, it's not safe to put it on any character's wiki -- some people don't realize, but that's what that space on the Wiki is for. It tells the tag parser what it's reading. If an artist is lazy and tags their pictures lazily, it's not our job to compensate.