Where N is your post number. In other words, the first post adds one word, the second adds 2 words, the third adds 6 words, ... the Nth post adds N! words, and so on...

I'll start:

Once

,when the

Fire Nation attacked, everything changed. Only

great destruction was brought forth during this tumultuous period. Dissidents were branded as criminals. Those who spoke out were pursued and persecuted mercilessly by

(4!)

(add the number of your post below so its easier for the next person to know how much words to write)

Aang the last Airbender. For this action he has been promoted to be the only fire storm bender ever. He enjoyed his polpularity very much. People brought cookies and gifts in honor for his "heroism". After some time the leaders of the fire nation noticed they were not the celebrated persons they expected to be. Just because Aang was a kid... So they started to hunt Aang. Fire fought fire storm. It has been a battle that all the people would have remembered for a very long time. With all the fire around, unfortunately all water evaporated. Sad story, they all needed it to survive and died. And noone remembered this battle for longer than a few days.

The End!

(5!)