Board Thread:Support Requests - Getting Technical/@comment-1065014-20130820040636/@comment-5454372-20130820043158

Hit the "Edit" button on the page. If you're in visual editor mode, look on the right hand side for a list of categories. Find the one which says "Character", and there should be a cross or a trash can icon next to it when you hover over it. Tap that, and it should vanish.

If you're locked into source editor, it should say  somewhere. Delete that, and it should remove the category.