Description
If you're aware of the trope, whenever you have a blue oni, you often have a red oni... Well, if I'm playing a blue oni, then I guess this lady here can be an example of a red one...
The relationship between the two can vary, but one would argue that the blue one is often the cool and level-headed one, while the red one is obviously the passionate and "fiery" one. In this case there's potential for some "odd couple" situations, but it really depends if I actually want to flesh out that universe or not.
But on the flip side, I think it's some good practice to draw the opposite sex of a monster race. The original (actual Japanese) lore of these creatures was that the males were fairly ugly but the women were always super pretty and could be simply mistaken for humans with horns. I simply couldn't have that dimorphic nonsense, and saw these "cousins" of orcs and trolls needed a more even representation across the sexual spectrum. Besides, tusks can be cute or cool... Also, being a race of brutes, I don't think you'll ever really meet an oni who'd be really thin and scrawny, and imagine that body types range from athletic to "strongfat" to gym rat kinds of builds. About the real thing I'm probably not gonna follow to a T is the whole tiger loincloths and spiked clubs thing... Because well, if you've got guns and the ability to afford halfway decent clothes, you don't have to rely on such crude options that much anymore.