if you favorite one of your own characters, they'll appear as a featured character! if you've only favorited one of your characters there will be one featured character, but if you favorite multiple the featured character will cycle upon refreshing the page :)
I'm just wondering because I thought it was random but now for me I've just got one character there, all the time.
Found out, thanks ^^
you can also remove the "featured character" box off your page by going to settings > display settings > front page settings, then uncheck "featured characters" and click "update front page"!