This is Darkness (fairy tail) (Third book to this is Nalu series)

You have had the love story of NaLu and the tragedy that faced Nashi after birth but now, years after everything went back to normal, we get a darkness that haunts all of Fairy Tail. Nashi is now 18 and fully matured, well mature enough to be in Fairy Tail that is. She lives the normal life of a mage and constantly spars with her father. Things start to get strange around Fairy Tail though and a war is coming. This leads to intense training and return of very close friends. Read and find out what happens.