Ok, this has been getting on my mind since I saw a fanart theory on deviantart. But BoomerxBubbles (the deviantart user) made an fanart with a theory on Starlight Glimmer taking Diamond Tiara under her wing and treat her like a sister (like Rainbow Dash and Scootaloo).
And that me curious on how it could work. And I posted a comment about this on Diamond Tiara page. All I got was one reply saying "well..........no". I want all you bronies and pegasisters to give me your opinions. Do you think Starlight Glimmer and Diamond Tiara would be like sisters or not? If you think so, why and how?