At first when I read your legend I too felt it was much too vague, but since you explained that that was for a purpose, I reread it and I think you can improve this piece by choosing your vocabulary a bit more creatively, and by checking your grammar. It will be more cohesive and clear without losing this vagueness. I myself enjoy writing mostly descriptions, so I really enjoyed reading your piece. The imagery is great. Why not also use adjectives for sounds, especially when you get into the battle details? And likewise for the other senses, where appropriate, for the rest of your story, perhaps as yet unwritten?
Now I would just go through your writing and offer my thoughts. This will probably seem teacher-ish but I really like doing this and I can't resist. You can tell me to fuck off if you like.
by James Light
Long ago, Mankind brought upon themselves a darkness that which to this day has never fully been undone.
(Check verb-subject agreement. You might say, 'Mankind brought upon itself'. Also, choose either 'which' or 'that' after 'darkness' not both. I forget which one is proper.)
Driven by desires for power, war swept the lands. Brother took up sword against Brother, soaking the ground with bloodshed that lasted an eternity. Kings fed their soldiers to Hell's mouth, determined to increase their wealth and influence in the world. Greed had taken them; possessing them like the fortunes they so wished to have.
(Soak the ground with blood, not bloodshed. Bloodshed is the verb; if you still want to say, in the same sentence, that the bloodshed lasted an eternity, you may need to rewrite it somehow. Maybe, 'Brother took up sword against Brother, causing everlasting carnage that soaked the ground with the blood of its victims' or something. And I really like the Hell's mouth idea. The last sentence here seems awkward; just make it clear that it is the king who desires and possesses the fortunes so strongly and not Greed. As you have it, it is not entirely clear.)
The world was plunged into darkness, in what is now known as the Wars of Sin. What was left of armies began to revolt, and overthrow their tyrant lords. But no man could be spared of Greed's influence. Soldiers began to fight over unclaimed kingdoms. Kings struggled to maintain control. War had turned upon homelands.
('Plunged into darkness, by the Wars of Sin' - you have a lot of this kind of passive voice in your piece. I would suggest cutting down on that. I think writing is more effective with more active voice, especially when you have a violent topic like yours. For example, 'These Wars of Sin plunged the world into darkness' or 'Greed spared no man'. Also, if the kings are still maintaining some hold on their kingdoms, how can soldiers fight over unclaimed kingdoms?)
Battles raged on, and escalated. Men began to hunt for objects that would give them the power to rule and control. But what they uncovered resulted in further destruction of the world. Man had ended its war against one another, and now banded together to stop the demons that they had released.
(I would tighten your writing a bit, for example eliminating things like 'began to' or common words like 'give'. Of course they have their place but sometimes it might be better to be more direct. Men didn't just 'begin to hunt', they 'sought relentlessly' or 'embarked on a desperate quest' - you see what I mean. With words you can illustrate the emotional highs or lows that your characters feel along with the trials they endure.)
They were not successful...
But all was not lost, for the Goddess, Felis - Mother of the Planet - would not see her children destroy everything she had given to them. In her weakened state, she gave one man the power to save the world. A man who was pure in heart. A man, who under Felis' light, would not succumb to the sins of mankind. With pure mind and blessed spirit, he alone would be able to stop Mankind's freefall into Armageddon.
(Try a variety of transitions. Instead of 'but', use 'however', etc. Your last sentence here seems strange to me. Can you in fact 'freefall into Armageddon'? Maybe it would be better to 'rush headlong into Armageddon'. Freefalling to me seems more appropriate for despair or hell. Actually now that I'm thinking more about it, it works fine. Anyhow it was a thought.)
And in the final battle of the Wars of Sin, he emerged victorious. The world was ravaged with war, but together Mankind could restore the light they had extinguished so long ago.
(Here I would empasize your hero instead of merely using 'he'. Even if you said 'This man emerged victorious', it seems somewhat stronger.)
The Goddess Felis appeared before the entire world, and gave to everyone a prophecy that should never have been forgotten:
(Here I would make it clearer that the goddess is issuing this prophecy after the wars of sin. At first I thought maybe it took place just after she created the world. The 'should never have been forgotten' part might fit better in your second-to-last paragraph.)
"Though you celebrate your salvation, you will forget quickly. You will forget the pain you have brought upon yourself, and the blood forever staining your hands. Life will return to normal.
(I would specify what 'normal' is. I mean, normal could be a nice quiet family life, or whatever it was before the wars, but it could be with or without the people having learned their lesson. That's what I meant you should specify. Or I guess maybe not, since you do so later on...)
"But like the waters I have given you, history shall be repeated. Time flows like a river into the oceans of the past, present and future. They are all connected, and you shall raise the depths of Hell unto yourselves once more."
(The water-time analogy is a good one, but you might word it a bit better in the first sentence. I understand your idea, but at first glance the sentence implies that water repeats itself, which is an awkward concept."
The words stung with worry among Man. But they also rang true. All was forgotten, and life soon resumed its normal pace...
(Again, nice thought but just phrase it better. 'In spite of the worry this prophecy caused man, its words rang true.' or 'While the words of the Goddess were a cause for grave concern, they were nevertheless realized.' 'In spite of man's consternation, the prophecy was indeed fulfilled' or something. I don't know. I just think it's a good idea that could be made more effective through improved diction.)
And now, this has become nothing more than a fairy tale read by children. It's warning has been ignored, and Mankind unknowingly prepares the Second Coming to consume the world.
(I might replace 'and now' with 'nowadays', and 'prepares' with 'paves the way for'.)
Thus is The Legend.
(I don't think you can use 'thus' this way. Thus means more like 'in this manner' or 'therefore'; as in "Thus Spake Zarathustra" so if you need to use it here you'd need to change something.)
So, Jamesman, I can see that it looks like I'm just trying to rewrite your story. But what I mean to do is offer suggestions as far as your vocabulary, mostly. Your ideas don't need help. You have so much in this piece to expand upon and develp for a wonderful story. Let me know if my thoughts were helpful or if I should go find a really high bridge.