King Garon (暗夜王ガロン Anya Ō Garon, lit. Dark Night King Garon in the Japanese Version) is Chapter 27 of Fire Emblem Fates in the Birthright Version. The player will not be able to save after completing this chapter, nor return to My Castle. The player will also be unable to capture units from this battle because of this. The Capture skill can be used, and the normal dialogue for capturing a unit will display. However, upon completing the chapter, when the player next returns to My Castle, the captured unit will not be in their Prison. This chapter takes place in Castle: Throne Room.
With countless trials, numerous losses, the Nohrian generals dead and nothing left in their way, Corrin and the Hoshidans finally confront King Garon in his Throne Room. Garon is "pleased" to see Corrin again, mocking them for making it this far. Garon tells Corrin that his family were all pawns for the war, angering Corrin, who knows that he cannot be reasoned with, and Corrin attacks him. However, their Noble Yato is unable to penetrate his armor, and in retaliation, Garon launches several blows at them. Azura attempts to use her powers to weaken him, but Garon is aware of this and grabs her, threatening to kill her unless they listen to his demands. Ryoma negotiates with him and asks what he wants. Garon demands that Hoshido unconditionally surrender so its lands can be incorporated into Nohr, then states that he wishes to kill Ryoma. Garon sends a fireball at Ryoma, wounding him.
When Corrin tries to figure out how they can hurt Garon and says they need more power, Ryoma's Raijinto suddenly reacts to Corrin's Noble Yato, empowering it into the Blazing Yato. Corrin decides to test the new Yato on Garon, and he screams in pain, stating that it actually hurt. He threatens them with death and calls for his soldiers to kill Corrin and the Hoshidans, but they fail and the Hoshidans fight and defeat him.
As Corrin celebrates victory, Garon, refusing to give up, transforms into the form of the Dusk Dragon and reveals them his true form. He attacks Corrin, destroying the Blazing Yato in the process. As Corrin is left speechless with what happend, Ryoma and Takumi attempt to fight Garon with their Raijinto and Fujin Yumi, but Garon easily wounds them. When he attempts to finish them off, Corrin protects Ryoma and Takumi from being killed, taking the hit for them, and fall into a near-death state.
Prior to the start of this chapter, the Avatar's Noble Yato will be upgraded to the Blazing Yato, increasing various stats and enabling them to partially hit through the Dragonskin skill that Garon has. This change is retained even if the player leaves the chapter, so if there are any last-minute preparations involving other battles that the Avatar was previously a little too weak for, trying them again with this upgraded weapon may be a good idea.
The enemy forces are far less numerous on lower difficulties. On Normal, the groups in the side rooms, as well as the Great Knights between them, are completely alone. On Hard, they instead have two units per group, while Lunatic brings the total up to four per group (besides the Great Knight groups, who remain at two), as well as adding a few more to the two side rooms in the back. In addition, the General in front of the player's starting location is joined by two similar Generals, and the Berserker in the middle of the map is joined by two others. These Berserkers have skills as well:
- The middle Berserker, who is present in all difficulties, has Vengeance, Counter, and Swordbreaker.
- The one to his left has Counter, Quick Draw, and Tomebreaker.
- The one on his right has Counter, Axefaire, and Shurikenbreaker.
As for the units surrounding Garon himself:
- The Sorcerer has Vantage, Duelists Blow, Tomefaire, and Lifetaker, as well as the Ginnungagap tome, making him a powerful foe.
- The Maid has Pavise, Aegis, Miracle, Countermagic, and Shurikenfaire, along with a Silver Dagger, Recover, and Fortify.
- The General in front, who only appears on Lunatic, has Pavise, Aegis, and Counter, along with a Brave Lance and Spear.