Can Riku sense what your character truly is? Yeah, it's nothing special.
If so, what are they and can he tell just by a passing 'glance'? Just another squishy human being.
On a scale of one to ten (one being Princess of Heart aka nada, thirteen fucking Xehanort), what level of "darkness" do they have within them?
Probably an eight, for having to work on criminal cases at a young age.
What do they smell like? really expensive "I have so much money but I'm not bragging as much as I should because I'm classy" perfume, paperwork and teacakes
What is your character's tolerance to dark magic? squishy human being
Can he break privacy laws and just teleport to where your character is? okay.