Does anyone like this plot for a manga im writing ( any advice)?

Long ago, the world was perfect in every way. Man would commit no sins, evil was not even a word. In all the world there was no wrongdoing. The nature of mankind was excellent and sinless. But all that changed when the seven dragons escaped from the depths of hell. Each dragon possed a certain sin. The dragon of lust, gluttony, sloth, envy, wrath, greed and pride. When they came to the world man became wicked, lieing,stealing, cheating day by day .The world became indulge in darkness. But one man remained righteous and he put a way to the seven deadly dragons and casted them to stone. And the world was again normal, or so it was thought. But the after effect of the dragon sinners were still in the world. And so it was that man was capable of sin .The world today lives divided by clans or lineage . The clan I once belonged to was called the “purified” clan. I have no memory of my real parents my mother died giving birth to me .. I wasn’t long ago that I relized that the world wouldn't be the same if I had not existed, it would go on rotating around the sun without me. I had no purpose in the world I had minus will be dead. Untill that night danso and his men invaded my village, our clan fought back but danso himself came onto my home. He pulled out his sword to stab me . It was my tought that I was already dead, I had no purpose. When he asked why I was not scared, I simply told him I had no true function on this earth. And he asked me if I wanted one. I told him yes! fair enough he took me under his wing. And he taught me me the most important principles a warrior must have. He must slay with no remorse show no emotions on the battle field for emotions, do nothing but cloud your judgement and allow you to not make smart decisions. His one goal is to unleash the dragons and so he can rule the wolrd and be known as the sin dragon master. And rule the world under darkness. Although his purposes to many are dreadfull. I do not care of them I care only about him, he is the one who gave me purpose and I will put my life on the line to see that his dream becomes reality. If I aid danso in completing his goal and the world does induldge in darkness then I will have a purpose. Since it is so without me the world would not be of evil.