User blog comment:Woest/Raven Tail/@comment-7418318-20131119113308

Precht (Purehito in the "old" translation) instigated the whole Tower of Heaven incident as a distraction so he could search out the "keys to Zeref's ressurection" in peace.

I think he told Ivan about Lumen Histoire for a similar reason, only that the plan never came to fruition due to Hades' death and Fairy Tail's disappearance, but despite that, the seeds were already sown.

Since Precht would have just used Ivan as an unknowing tool, I doubt he'd tell him any more than absolutely necessary to get what he wants out of the situation.

I also highly doubt that Mavis would have told Zeref anything about Lumen Histoire.

Whether Ivan knew about Obra's true allegiance and origins though is an interesting matter. Was it a kind of Faustian pact, or was Ivan just played by Zeref and Obra?

I think the former would open up more possibilities for interesting stories in the future, so I hope it ends up revealed that Ivan knew about Obra's identity and had some kind of deal with Zeref, beyond just gaining a strong member for the GMG.