Originally Posted by TAScientist
Cass is a Noxian, and if memory serves, all Noxians are required to serve no fewer than 6 years in the military, so idk about "no history of combat"
Millitary service does not always constitute combat. Her lore basically flat out states she was a spy who use her body to gain information via pillow talking.
"... Cassiopeia - despite lacking her sister's killer instincts - was equally renowned in at court for her stately character and elegance. Cunning as she was beautiful, the temptress could never be found far from the arm of any foreign dignitary, her wiles prying secrets from the lips of even the most wary attaché."
Not to say she isn't strong now, in her reflection she lifted up a bodyguard by the neck with one hand, that's pretty impressive. She also slaughtered a group of servants directly after her transformation.