FRIENDS.
Are you loyal to the cause?  Do you stand for order in a world of chaos?  Have you proved your worth?  If you answered "yes" to those questions, you might cut it as a friend for Rell.  She isn't a terribly emotive person so she doesn't show her affection in very touchy feely ways, but she does her best by those she considers friends. 

LOVERS.
Requirement #1: being a woman.  Requirement #2: being loyal to the cause.  Rell won't waste her time with you otherwise.  Ideally, she would like a long term, committed relationship, but she has been known to indulge in the occasional short-term fling.  But once she commits she's utterly loyal and will never forgive a betrayal.

ENEMIES.
Dissenters, rebels, and non-humans are at the top of the enemy list, followed swiftly by those who might consider her a tainted upstart with no right to the authority she now bears. 

OTHERS.

Other than that... idek.  It might be interesting to have some people from her past, from when she was growing up.