As far as I know, you can't change the bold name at the top of your portrait, which says currently "LilithThanheim." When you go to your profile settings, you can hit the star on which character you have that will make it your main (and visible) character. This is the picture that you see, and to the right of it will be your character's information (which currently says you are "Stiitch Hunahpo"). So you'll still show other folks who you are, just not with your bold titular. Hope this helps you!