He's dead. Actually, I slaughtered him three hours ago.
I was lucky, he only used Grand Cross two times, which doomed some characters and braught their hp to 1. Nothing serieus. And Zidane and Steienr came in Trance.
It's strange, I tried this morning 7 times, and I got my ass ahnded to me (LoL), then after 4 hours, I try again, and I win in teh first try. It can only mean one thing; You need luck when taking on Necron. Hoping he doesn't use Grand Cross too often.

I'll post a "My thoughts on this one" topic soon, like I did with FF V.