Necron?

[Goldenboko]

But anything that they said about Necron they didn't spell Necron's name anytime, this is obvious...

Foreshadowing. Its means to give hints to future events. To me it would be odd if ANY of the characters knew Necron's name because how would they know, Necron has never been seen by any living human eyes at the time. What matters is theres many points where they tend to hint toward Necron...

The problem now comes whether you believe Squall of SeeD or the idea that Necron is the antitheses of the Crystal.