Here are some instances : my friend gave me one, someone dropped it and i picked it up, i bought it, i got it from the daily boxes, i scammed someone and took his fairy, and so on.
HOWEVER!!! If the question was "Lore-wise, where do you get the Fairy of Water Energy from?", the ONLY POSSIBLE ANSWER would be "Time Space 33", cuz' y'know, after you get the Fire Fairy Mimi is like "Omg go to Eva to learn more about Fairies, congrats, you are gonna be more powerful and you will help Nosville even better in the war against the Koaren and the Kenko!" and as you progress through the quests, you will also receive more and more fairies to boost your powers (Water, Light and Dark). But hey, I bet nobody from Gameforge even knows about this, I mean, you need level 75 to wear SP5, RIGHT?
My problem is the fact that the possibilities for the answers are endless and everyone with an IQ above room temperature can agree on that. Seriously, where can I apply to be a GM It's about time someone put actual effort into hosting events and stuff.