Nya
It’s not that Nya doesn’t like you.
It’s that she can’t be bothered to care.
As a genetically enhanced cyborg cat, Nya posesses several attributes that put her above her peers, including a prehensile extendable tail, electromagnetic grips, onboard cranial computer, improved reflexes/vision, and an intrinsic knowledge allowing her to master any weapon or form of physical combat. All acquired through unknown, or at least undisclosed, means, these maker her physically superior to everyone else.
And she knows it.
Her clear physical superiority has led to a likewise effect psychologically, as she considers most everyone else beneath her and thus not worth her time or effort to bother with, aiding others only when she stands to benefit.
Or at least, that’s what claims, both to others and to herself. Her seeming vanity, as indicated by her limitless supply of custom outfits, and the fact she continues to hang around individuals who drive her insane, like Mew, betray a more complex psychology; lending credence to the possibility that it’s not that she doesn’t care, but that she doesn’t WANT to care.
Whatever the case, Nya’s abilities/mindset lend them well to both medicine and assassinations. And guess which pays more?