Link must navigate a long series of corridors in the Depths beneath Hyrule Castle riddled with enemies, and upon nearing the bottom, his Sage Powers get disabled. This terminates in the same location seen in the opening cinematic and the final boss battle with Ganondorf.
Once Link jumps off the ledge at the Sealing Chamber and lands on the platform below, war breaks out against The Demon King's Army. For each of the Regional Phenomenon (and Guidance from Ages Past) that Link has completed, their respective Sage will arrive as a reinforcement shortly into the battle (and, if at least one reinforcement arrived, remove a single Bokoblin in a scripted event as the fight begins), and as a result, re-enable their sage powers. After the last Moblin falls, Dungeon bosses begin to get summoned, in the order of Colgera -> Marbled Gohma -> Mucktorok -> Queen Gibdo -> Seized Construct, and Link must fight them if he did not already do so in their respective dungeons (if he did, then the respective Sage deals with them for Link). And lastly, if the fixed Phantom Ganon encounter in Hyrule Castle's Sanctum was not defeated, then 2 waves of 5 Phantom Ganons each must be fought. Only after all these battles are over will the barrier shatter and a path to Ganondorf be made available.
The battle with Ganondorf has three phases. At the end of the second phase he eats his Secret Stone and becomes the Demon Dragon. The Light Dragon appears and assists Link for this aerial phase of the battle. Link must destroy four pods of eyes on the back of the Demon Dragon, then destroy the Secret Stone on its forehead. After this Ganondorf explodes in a column of light. A cinematic occurs in which ghost versions of Rauru and Sonia appear and assist Link, turning the Light Dragon back into Zelda, then disappear. Link falls through the air as the player resumes control and must dive to catch Zelda. The pair dives into a body of water, then Zelda awakens in a field of grass. She observes that Link is present holding the Master Sword, surmises that the Demon King is dead, and is surprised to find that she has reverted from her Dragon form. The Find Princess Zelda quest is marked as complete before the credits roll.
The Destroy Ganondorf quest is given to Link by Purah at the Lookout Landing, but only after completing the Crisis at Hyrule Castle, the Find the Fifth Sage, and the Recovering the Hero's Sword main quests.
|Wind, Fire, Water, Lightning, and Spirit. The five sages have awakened and entrusted you with their power. You still don't know where Demon King Ganondorf is, but Purah says she suspects the Depths. If you work with Josha, who has been investigating the Depths, you might gain a lead.
|Wind, Fire, Water, Lightning, and Spirit. The five sages have awakened and entrusted you with their power. You also determined the Demon King's location during The Depths investigation. All that's left now is to head to the deepest area of the Depths beneath Hyrule Castle and defeat Demon King Ganondorf.