The prophecy of light and amber (English)

Morro didn't attacked for a while. Last time when the ninja almost defeated him, he escaped. The bounty is repaired and they live there now, away from New Ninjago City. The ninja train everyday, waiting for the moment that Morro returns. But then, the ninja found a scroll. There is a prophecy written on it. Morro, the ninja and two mysterious persons are on it. Together, they defeat Morro, but who are that mysterious ninja? Why do they help to defeat Morro? And whee can we find them?