Behind Me (Relationship Between Natsu and Zeref)

Natsu is the younger brother of the to be Dark Mage Zeref. When darkness begins to appear in Natsu's heart Zeref does everything he can to be sure the darkness doesn't take control. In this story Natsu is between three and four years old and Zeref is close to being ten.
All rights of Fairy Tail characters belong to Hiro Mashima. I only came up with the story idea.