In summary I only recently found out how to mark a character as a character in the tags for e621. Issue is tat I went back to edit this one https://e621.net/posts/2805399
It is an approved picture, approved by Shadowstones, but when I go to edit the tag to make it correct all that comes up is "Failed to update the tag category for the following tags: ashe_kazuri. You can not edit the tag category of existing tags using prefixes. Please review usage of the tags, and if you are sure that the tag categories should be changed, then you can change them using the Tags section of the website." and I really need help with trying to fix it so it is right.

The tag itself is "Ashe_Kazuri" but I can't seem to fix it to make it the character rather than a whole tag in it of itself.

Sorry if I did some stuff wrong, this is my first time posting onto the forums itself

Edit: It has now been fixed. Thank you very much for the help, Slyroon!

I fixed it for you.

For reference, you probably tried to use "character:" in front of a tag that already exists (you had created before). AFAIK only Janitors and up can change tags like that.

When it already exists, you need to go to the tag page (the "?" on the side of the tag name), and click "Edit Tag" on the top menu. There you can select "character" in the dropdown.