By your responses to comments in this thread, I get the impression that she is a very well-conceptualized character. She's like a staple food, nourishing but nothing to get your taste buds all a-tingle, and you're looking for some spice.
She is stolid and dependable, a salt-of-the-earth type, which we all depend on, whether in a game or the real world.
She also sounds lonely. Her time in the orc army surrounded her with like-minded comrades, united in a focus on gaining success in battle.
Now she's amidst allies who apparently take her for granted, and (through your agency) she's experiencing something of an existential angst. Her new comrades have different world-views, different confirmation biases. She has become a minority, adrift in a mainstream culture (to the extent that the party is the whole of the culture).
Lyrics from the late singer Peggy Lee's hit song come to mind:
"Is that all there is?
Is that all there is?
If that's all there is, my friend,
Then let's keep dancing.
Let's bring out the booze
And have a ball."
In Human's situation, one could substitute the word "fighting" for "dancing".
Her natural reticence keeps her from acting out, practiced at tamping down her own feelings and deflecting any inner resentments.
I think she needs a hobby.
If you're just looking for something to give Human more "living color", maybe she could add some new pastime to her repertoire, something outside of her usual activities. Bird-watching? Collecting some class of items?
Maybe, in her downtime between adventures, she could become an instructor for a local militia. That would be more in keeping with her lifetime of focus, but ... let's start from there and give it a twist ...
All that melee training has given her a lot of experience with the importance of footwork (especially with her enduring leg injury).
Can you see her parlaying that into an appreciation for dancing? Depending on the culture, it would likely be in the line of folk dance, and might be limited to festivals and/or celebrations. It would keep her physically active, and provide that lift to the spirits that exercise, even moderate, is so good for. Her stubbornness to overcome the problems her bum leg presents could be a part of it.
Seems I've come back around to Peggy Lee. Sheeesh!