User blog comment:Ncduru/Who is Anna?/@comment-5266348-20151202030308

I doubt she'd be their mother. He would have addressed her as some form of "mother" if she was, and the back story we've been given thus far makes Zeref and Natsu being orphans seem likely (the whole "I have my brother's body preserved" thing).

Sister is unlikely from the point that if they had one, it's difficult to not see her appearing during the flashback if she was alive and active at the time Zeref was cursed.

Childhood friend, is possible but unlikely. You'd have to explain how she survived Zeref's first killing burst which was implied to have killed the whole school.

Another chick interested in Zeref, is possibly but unlikely. While he certainly has the time - 300 years from curse to Mavis, then 100 years to the present - they'd be unlikely to last long. It seems if someone that's cursed so much as touches someone they're on friendly terms with, that person's life is extinguished. That's in addition to the death waves.

Odds are decent she's related to Lucy.

Lucy = Lucy in the Sky with Diamonds Jude = Hey Jude Michelle = Michelle Layla = Layla

The first three are named after song titles of the Beatles. The fourth for the title of a song by Eric Clapton, partially inspired by the wife of one of the Beatles.

In light of that, Anna stands a non-zero chance of being named for "Anna (Go to Him)", a song originally recorded by Arthur Alexander, but for which the Beatles did a cover version, which appears on one of their albums. Keeping to naming scheme of Lucy's family, making likely she's a family member as well.