Faction Two is literally based on Faction One, indeed a creation of F1
When Planet Phaeton (between Earth and Jupiter) exploded only a few of its giant humanlike inhabitants could escape. They made it to one of Phaeton's moons called Mars. Unfortunately the refugees had to undergo genetic modifications to survive with far less oxygen. So they injected themselves with DNA material from the lovely 'frogensus hoaglandia falkowitski' dwelling on the southern slopes of Mons Olympus.
One ancient clan of these modified Martian Phaetonions (spelled 'fat onions') then set out for the blue planet Terra aka Earth to see greener pastures.
Well, they embarked into Stargate V spacecraft and were about to pass thru the 'Van Allan Belt' when the next disaster hit hard: Due to unforeseen increased neutron bombardments their DNA tissue partly dissolved and affected the outer appearance of these brave space travellers.
When they had left the Van Allan Belt all of them felt so 'froggy' but only later on after touchdown on earth's surface the full impact of the radio-active alterations was to bee seen: The alien arrivers occasionally looked more like Martian frogs than transformed humanoid giants from majestic Planet Phaeton (RIP).
This is how the 'modus operandi' of shapeshifting had developped.
One tuff lady however had invented the ACM Activated Cellular Memory technics and thus had succeeded to stop the uncontrollable shifting mechanism. She could shield off the radionic trigger waves and she was able to keep a stable humanoid appearance as long as she wished to have.
In remembrance of this ancient lady from the martian colonies and her great success in fighting the Van Allan effects with mental radiation only, the martian clan decided to archive her story as Ray Van Allan Bravery in the Holy Martian Exodus Scriptures.
The benign reader is hereby inspired to make own decision.