Picture it! The ending should have been a tragedy at the collapse of Numenor with it devolving to Morgoth Worship and barbary while The King leaves to conquer some of the undying land, with Sauron remaining behind to rule while for Ar Pharazon but in reality ultimately planning to ditch Numenor knowing full well The Numenorian's don't stand a chance, some of the protagonist leave when Elendil convinces them the that the Island is doomed because of his visions and they must flee immediately with others, half the party however say they are staying behind ultimately thinking with emotions high and under misconceptions they have been led to that they can stop him and then they attempt to confront the Dark Lord.
This all results in Sauron being confronted, arriving at the Temple of Morgoth the remains of the protagonist party or group find him wearing the face of one of their former comrades from a few seasons prior who they had cared and loved having felt he died a hero now covered in blood surrounded by bodies of dead sacrificed Dark Priest of Morgoth.
Sauron laughs at their distraught face's before thanking them for their help his eyes glowing red slits revealing his nature before saying a phrase or saying something that would only confirm to them that their friend had never existed and was only an illusion to deceive them.
The Dark Lord would then silently begin shifting to various appearances he took throughout the series, no matter how minor to further impress how close yet so far, they ever were to truly uncover him, much less stopping his plans.
The leader of these protagonist would shakily draw a weapon prompting his fellows to nervously do the same, the sword itself being a Mcguffin that all of the protagonists had searched for off and on over a few seasons while doing other things under the rumor that the Dark Lord had feared it only to now reveal to be worthless as Sauron himself had been the ones to lead them to it.
Sauron would taunt them further asking if the others in their party had died unaware of the currently happening departure of Elendil, thinking it a shame that he had intended for them to all arrive here under some misconceived notion of defeating him so he may kill the last of the loose ends personally before leaving the Numenorians to deal with an inevitable host of Valar when they arrive.
Even through his fear and despair at that moment one of the protagonist a man with a bow realizes that though they are doomed, Elendil was right, and Sauron realizes they are escaping may move to crush the exiles before they depart and shoots an arrow which hits the Dark Lord now back in the form of their friend in the shoulder who only laughs and taunts in the manner of which they remember before his voice grows darker and darker as does the shadows in the room.
Their friend then erupts in flames forming the shape of the armored Lord of Mordor sitting on the rock throne, mace in hand and one ring on his finger which would be the first time it would be seen in the series.