>>538170435
I, basically assume, that they just have MMO-like stats, rather than physical characteristics. Like, their halo actually stores all such data (purely my headcanon), like their strength, durability, speed, and even ammo.
That's why they can be short, but be stronger than tall person, and so on.
So, in other words, Sumire just has more physical stats. It has nothing to do with her "skin".