Gash_V-D_Hetchum said:
And with the part about previous arcs and overall plot, Nirvana arc was also the arc that introduced Wendy,
Nirvana was destroyed, its healing function was lost when all the lacrima were destroyed. But the council may have had the remains sealed. They did so with Lullaby.
Another potential arc?
Council Rebellion arc? A evil faction exists within it, who tries to revive Nirvana and use it on Zeref?
I think Nirvana was not totally destroyed.
And I'd like to think that besides character introduction there were several hints for the future (e.g. In the fantasia arc we saw Ivan and Gazeel working as a double agent, the more you remember the more you realise). In the same way I view the Nirvana arc: a new character and another piece of the puzzle. The "400-years ago" phrase was TOO suspicious.