Hao Pharmaceuticals
Base of Operations: China
Aesthetics: Organic, living and breathing, very similar to the monster girl like aliens assaulting earth.
A multinational corporation headed in Beijing, Hao Pharmaceuticals has made great strides in it’s research of cloning technologies and fabricating organic tissues. Playing to their strengths, they’ve taken a very unique and controversial approach to creating their own colossal protectors:
They have taken to creating living bioweapons using DNA from felled alien giants, training them from birth to follow orders, and placing large chips in the backs of their neck which would administer a powerful electric shock if orders are disobeyed, or detonate as a last resort, killing them in case they go rogue.
The EDC
Base of Operations: Multiple bases scattered worldwide, the largest is set in the Australian Outback
Aesthetic: Very cobbled together looking, made from whatever was available at the time, often adorned with propaganda slogan graffiti.
The EDC (Standing for Earth Defense Coalition) is a radical anarchist organization that puts no trust in the world's governments and megacorporations, and has declared it's intent to create their own colossal defenders to supposedly protect "the citizens of earth, regardless of creed or nation"
They were initially dismissed by most major factions due to their apparent lack of funds, resources and researchers. But the EDC surprised the entire world when they rolled out their very own mechanized giantesses.
Shanghai Robotics Company:
Base of operations: China
Aesthetics: Sleek, modern, red, green, and gold color color scheme for a patriotic look.
A government owned company, Shanghai Robotics Company (SRC for short), was founded in response to the alien attacks. Not wanting to fall behind the west (or worse, Japan), in the giant robot industry, the government spent millions to create a giant Mecha as quickly as possible. Their main concern is looks however, as the government wants the prestige and propaganda potential from having a giant robot first, with the defensive uses of the mechas being a secondary priority, with then planning on making better models after their first's debut. They will definitely succeed in making their own giant robot, how said robot will fair in battle is another question entirely.
Organization of World Domination
Base of Operations: Somewhere in the Pacific Ocean
Aesthetics: Think if Dr Evil and Skeletor got together and designed this thing
An evil secret society of villains from all across the world who have come together and formed the OWD for world domination. By stealing and combining the technology and innovations of other robot companies around the world, they've gained the ability to build their own Mecha giantess(es) to serve their own evil schemes for world domination.