User blog comment:Skitzo1/A Natsu - Zeref theory/@comment-16344653-20130106043027/@comment-63.140.110.241-20140912161001

Maybe its wierd, but think about it, in the alternate future, Natsu swallows up what looks like igneels fire and attacks all and any dragons he can get his hand on. It looks like they are dropping too. So basically he and the few survivors, survive by hiding in the dragons time. Many of his guildmates are fighting and he is consumed by his desire to protect Lucy and the remaining survivors. He therefore attacks all dragons, not realizing that some are his friends, for the sheer quantity of them. When he's defeated so many, he realizes his mistake, maybe by killing igneel or something, but too little too late. Horrified, and energy depleted he gets attacked and nearly killed by a dragon. Touched by Natsus passion, love and regret, Zeref than splits Natsu's soul and puts Natsus ferocious power, grief and darkness into the form of acnologia. He does so in hopes to keep a piece of what he considers the purest form of magic alive,  even though the world may end. However, since he is a dark mage, the power that acnologia holds becomes corrupted and acnolgia loses all memories and emotions except rage and end. Realizing what HE did Zeref wants fix it. He and Mavis work to preserve Natsus remaining light and life force in lumens historie, with the idea that if Natsu can kill acnologia or Zeref, the world can be returned to balance. To complete it Mavis must put her life force into lumen histories as well, and Zeref must sleep. Since Natsu is the key, if he can kill Zeref or acnologia the era will be in balance Again.