Demon and Fairy

What if Natsu always knew he was E.N.D ? What if he knew he was Zeref's brother ? What if he was actually working for Alvarez? What if he was more powerful than even Zeref himself ? What if he had killed Igneel a long time ago, after he had succesfully learned the fire dragon slayer magic ? What if he lost all his memories after his battle against Igneel ? With all that, what happens when Natsu suddenly remembers everything when he get to see Zeref on Tenrou ? A lot of fun !!! Warning: I changed some little things in the story to make it a little more interesting. As such don't be surprised if some characters have slightly different past or relationship.