Agni is the leader of the new Boboobian Ninja. He leads them under new morals and guidance. While still ruthless in their missions, they are now dedicated to Hapori Tohu and Bobooba, as well as to the well-being of all Matoran.
During the events of the second movie, he was against Bormatu's plan from day 1, and managed to gain a rebel following among the ninja. To this day he considers Bormatu a fool, despite having worked closely with him before he turned.
While he does believe in prophecies, he does not believe in their dependability and accuracy. He knows full well that prophecies come from Destiny, a force that predicts events as they should unfold, and not from time itself which contains events as they WILL unfold. As Destiny can be ignored and violated, as well as change and adapt, Agni considers The Guardian's telling of prophecies to be less accurate than weather forecasting.
Turaga Hakari may think the same way.
For the Official Bionicle Canon Ta-Matoran with the same name, see http://biosector01.com/wiki/index.php/Agni