In the world of Golden Heart, there was a time that a deadly toxic gas invaded the entire planet, every corner covered in a purple yet thick fog, anybody who breath it who have a terrible illness and a quick but painful death, but that was just the begining, then when it seemed to fade away, it only got mixed with the air, now making invisible for the entire humanity to know where it was safe or not to breath the air of the place, assuming the fact that not everybody made it to underground bunkers for survival, some sacrifices had to be made for the benefit of the species, but there was something strange about this purple gas...it only affected humans, not other animals like the monkey or gorilla since the animals on the zoo looked completely fine, we know all of this thanks to people that wear special radiation suit to go out and research the current state of the enviroment, plus, it was discover that the gas emits radiation which made it even worse.

So a group of scientists started to research what could they do to stop or do something for the survival of humanity, taking varios animals to the lab and searching for a clue to their inmunity to the gas, but sadly, no logical reasons or explanation as to why this happen...

But this ray of hope fell on to everyone when a anonymous scientist only called ´K7´ appeared to give the scientists a more advanced technology for research, plus a full document in PDF and in physical, containing an advance research of the gas, what was it,what illness and how to prevent it from expanding.

result is, she already made a sample for preveting the effects on a human inyecting modified animal DNA onto a human DNA, being her the first to use it, seen that it worked, they made several copies from the sample.

once inyecting every human with this special liquid, they could finally go out and live like normal people again!...

except that withing some months, the people started to noticed some ´secondary effects´of the inyection, some people grew tails, other people had their original ears replaced with animal ears, while other grew scales, fur, and even extra parts like wings or fins...finally, everyone became a anthropomorphic animal...

everyone became mad and tried to demmand the scientists due to their failure, while other found it really cool and accepted their new bodies really quickly, but in the end, everyone could´nt get back to being their normal selfs again.

But K7 was the only one who didn´t change at all, resulting that she made a small change to the liquid she inyected, and then she confessed that she was the cause of the purple gas; and the liquid inyected to everybody else, was to transform them into their ´Soul Animal´, some transform into mythical dragons, others turned into insects, and also as a bonus, got their physical abilities increased dramasticly also getting magical and natural abilities, like flying or breathing fire, temporarly increasd of their speed or strength beyond normal and much more...

but before she was assaulted and interrogated, she was found dead in a cemmentery, posibly a suicide due to pills found next to her, and a note written in blood that said:

`Let´s see how well ALL of you live now!!!`

looks the reason of why she did this to humanity is going to maintain itself as a mystery forever...