If all your monsters are sent to the Graveyard simultaneously by the effect of "Cyber Jar", "Raigeki", etc. and "Axe of Despair" is equipped to one of them, you cannot Tribute one of those monsters to return "Axe of Despair" to the top of your Deck. You also cannot Tribute one of the monsters Special Summoned by the effect of "Cyber Jar" since the timing has passed.
Since "Axe of Despair" activates in the Graveyard, you can Tribute a monster to return it to the top of your Deck even if "Imperial Order" is on the field.