The story can be read here.
Mu Mew Myu is a Tokyo Mew Mew fanfiction that takes place in an alternate universe (an AU fic) in which Mu Aqua was discovered during the heyday of the Second World War, and subsequently used in attempts to create super soldiers. After the end of the war, the programs were all shut down, and the use of Mu Aqua in human experimentation was outlawed in many countries. Then one day, Ryo Shirogane (an astrobiologist because that is my head canon) comes along and discovers that there may or may not be an alien invasion headed for earth. Using his late father's research, he comes up with a plan to use something presumably found only on Earth in order defeat the aliens. Needless to say, everyone thinks he's crazy and he's forced to flee the country because he'd already started experimenting with Mu Aqua which he "forgot" was illegal. Things were rough for him for a while until NASA was able to back-up his claims and contacted him to listen to his proposal. A rough research team was formed, and after nearly a decade of work, they finally achieved their desired results just as the aliens were making their final approach (because, you know, space travel takes a long time guys).
Character profiles will contain spoilers, but only up to the point where the story is written. Details about future chapters will not be revealed for the sake of ~dramatic effect~.
Scientists who do science-y things. There are now five of them total as opposed to the original two (technically three if you count Ryo's father), to fit in with how certain elements of the original are changed to be more realistic. Only three are left actually working though, since one died and one is in prison.
Beta Generation Mews
The main Mew team churned out by the Mew Project. These five girls all voluntarily participated in the project for personal reasons, or to seek a reward of some sort. They all underwent a lot of testing to ensure they'd be the perfect matches for their animals, and continue to have regular examinations to make sure nothing bad is happening to them. At the beginning of the story, Chimera have only just started appearing on Earth, so most of their prior training was theoretical or sparring against each other.
New Generation Mews
The team that the protagonists belong to. Their injections took place under questionable circumstances, and they had no say in anything. These girls were thrown out into the field with no prior experience using their powers, and are pretty much just flying by the seats of their pants and trying to stay alive.
Mews who are not part of one of the two main teams. They are all allegedly earlier experiments who were infused before the two main teams, and they have skill sets that differ slightly from the others because of this. Some of them are dead, some aren't, one's a sort of vigilante, I'm kind of just playing these guys by ear.
Obligatory alien antagonists featuring all the canon aliens (with the exception of the Blue Knight due to prominent lack of Ichigo) and two new ones. In this story, a line is drawn between those who are born being able to use magic (the canon aliens) and those who aren't (Kazuo and Mocha). Because of this, the canon aliens mostly fight using their magic, while the "dirty work" of controlling Chimera Anima is left to Kazuo, and Mocha just does what she wants.
Other characters who aren't magical girls or aliens. Mostly the human relatives and friends of the main characters, plus Luna. Some are more relevant than others, but they are all recurring characters. The list keeps changing as I add/remove characters and remember ones I forgot to put in there already.