Who Is Osiris in ‘Moon Knight’? The Egyptian God Holds All the Power

Eventually, the creatures of the Duat start trying to drag them down, but when Steven sacrifices himself for Marc, the scales balance. It’s Marc’s acceptance of why Steven existed in the first place, and Marc’s newfound ability to make himself whole once more, that allow him to finally face Osiris.

We actually met Osiris briefly through his avatar in Episode 3 when Khonshu calls a meeting of the gods together. Osiris is the god leading the meeting who informs Khonshu (and Marc) that they do not “meddle in the affairs of man.” However, now that Arthur is seemingly meddling in the affairs of the gods, perhaps Osiris will have to change his mind.

Source: https://www.distractify.com/p/who-is-osiris-moon-knight