HALO 3 question?

[Joey C]

I'm in the story right now and i noticed theres an alien on our side, why is this can anyone tell me, i thought i remebered something from halo 2 about him, but i cant think of it. so can someone tell me what his story is and why he joined the humans

 

[supergohan_2478]

he had to join cause this big thing under the sea said that earth will destroy the universe or some crap, so he helped master cheif and stuff

his story is that he was helpin kill master chief in halo 1 and got demoted or watever and become the arbiter. and so hes off kickin covenent butt and stuff who want halo or earth to activate