Updated my orignal post with colored versions...
And here is the explanation:
Angelica: Okay... This is a traditional scientist / cyborg figure. When I think about a mad scientist,
s/he always has to have a red sweater and dark trouser (and the lab coat).
To make her more "cyborgish", her left arm is not fully complete (only some wires visible) and the
headphones are part of her. Also if you look at her neck - you can see it is made from metal.
Henrietta: Somehow first thing I though about gaming was childish innocence... Thats why Henrietta
is a chibi with some sort of a gaming magazine. Headset is for the same reason.
Triela: Street Fighter Wriggle with mechanic arms? Well, the arms were inspired by the
HAL-suit, and backpack
is usually good for transporting stuff...
Why she looks like a Street Fighter character? Well, that is just how she turned out.