Keimrael was a pirate with a ruthless crew before she traveled to Limsa and started hearing the Echo. She started as a Lancer and Dragoon, picking up Archer and Dark Knight along the way but mostly sticking with a lance. She can do some magic, but she does not feel she is proficient at it, and much prefers physical DPS and tank roles.
It took a long time for her to trust and accept the Scions when she first met them, she'd had pretty low expectations of other people after many years of disappointment and frustration, but now she would do anything for them. The events of Heavensward hit her very hard, and she vowed never to let anything like it happen again. She constantly teases Estinien about being the Real Azure Dragoon™, and they have a friendly rivarly over it.
Keim has very strong opinions about agency, and not forcing people to do things against their will.