User blog comment:Woest/Raven Tail/@comment-4829046-20131119155845/@comment-24066070-20131119180856

Since Makarov mentioned that Lumen Histoire is "what Mavis wrote about the true nature of FT", maybe Zeref just wants to know the content and if it is dangerous to him he'll dispose of Ivan.

I suspect LH to be some sort of scroll which contains specific knowledge about Zeref, like his weaknesses or how to cancel his "immortality". After all Mavis was known as the Fairy Tactician, perhaps she devised a strategy to beat him and recorded this in LH. Although this may be overthinking things, since if this was the case, then Precht would've destroyed/moved or sealed LH for all eternity.