The greatest of the psychohistorians is put on earth in the service of the Emperor 100 years after the Heresy. He is given unlimited political power and his own lifespan (~100 years) to construct and start a plan to save the empire of man. The plan can take any amount of time you want, Seldon can leave anyone in charge you want but his own life is that of a completely standard human and you can not extend it in anyway. Can the power of psychohistory fight grim dark to a stand still? Assume Seldon has all the knowledge the Empire has collected to this point on the alien races and how the behave.

Can he make a plan to save the emperor and rebuild the empire to its former glory? Can he make a plan to wipe out the orcs, control the orcs or marginalize them? Can his plan minimize or outright stop the gods of chaos? Can he save the galaxy from the incursions of the Tyranids? Would he use races like the Tau and Dark Eldar?