User blog comment:Miskos3/Fairy Tail Chapter 326: Natsu vs. Rogue, Review/@comment-7418318-20130411123353

While rewatching episode 121 I noticed something Zeref said: "But after a certain day, I learned the value of life".

I wonder if he might have met the Fairy Tail members in the past (timetravel through eclipse) and learned the value of life from their actions.