Requirements for getting halo 3 skulls?

[mitch_p_hoffman]

I need some skulls for the hyabusha armor. what are the requirements for getting them......for example in know it can't be on easy....what else?
Do you have to start on mission start or can you start on rally point alpha?

 

[Sonicfan#1]

Well you have to go through the whole level until you find one and you dont have to carry it all through the level.But the skull on the level the covenant the last skull you get the iwhbyd skull you have to finish the level wich is basically walking to the exit.And you have to do it on either normal heroic or legendary never easy.