Ruby Throne was born into a small family that lived in a small town. Ruby herself was a bit small for a unicorn...but she had big dreams.
She has always been good at tailoring and fashion in general. Her goal is to one day be accepted into the School of Royal Tailors (located in Equestria) so she can train and maybe one day be tailor for Princess Celestial herself.
To her surprise...she does get accepted! And it doesn't take any effort on her side. But the reason will disappoint her...make her feel unworthy...and of course she won't learn it till after she is in the school.