10 Things We NEED To See In The Rings Of Power
5. The Siege Of Barad-dûr
When Peter Jackson included the Battle of the Last Alliance in the prologue of the Fellowship, he obviously couldn't include everything that went down.
In Tolkien's writing the war lasted for 12 years, many of which were fought outside the Black Gate. Thousands of elves perished during this stage of the battle; the slaughter they endured led to the creation of the Dead Marshes.
Even after the forces of good defeated Sauron's main host, and breached the Black Gate, the siege of Barad-dur lasted an additional seven years. Of course, it's doubtful the show will depict this, but they'll likely expand on everything Jackson established. Every race in Middle-earth fought in the battle, on both sides of the conflict, all except the elves who could not be corrupted. But this would mean we might see evil dwarves for the first time...
Eventually Sauron emerged from his tower to do battle with the leaders of the Alliance. This is the moment we saw at the very start of Jackson's trilogy, and will likely be one of the final events in the series.