yes it was answered, they said it had no purpose.
There are SUS, well, i dont know that for sure, but thats what they said, and gave clues and shit.

They gave about 3 different answers for it.
One of them said 'There's no use for it'
another said 'I'm not sure I think it has a purpose'
and another said 'What ninja star?'
so there you go...probably nothing.

Actually, John Vogel, after someone said "It has no purpose," said "and Without Purpose we would not exist." Ermac, I belive had said this at least once during Konquest. This may involve Ermac is some way.

The Ninja Star will release you from the Matrix.

Will it release us from sucky questions asked on fightnight? perhaps...let us travel back in time to get it done right?

it must have somthing to do with ermac and when you look at it in konquest it says " this throwing star might be useful somerday " but we have no idea what day that is

Guys, stop fooling yourselves. I was the biggest supporter of SUs before Fight Night but even now I've come to accept it. The Ninja Star is nothing, that was settled. The team made it seem like they were leaving hints, but they were kidding around. They were just fucking with us because they're all douchebags. I'm sorry to say it, but just let it go.