After the destruction of the Regalia, the group, minus Prompto, look to their objective. Zegnautus Keep.

Gladiolus: Are we seriously marching into the capital empty-handed?

Y/N: Well, the only weapon we have on board is the Ring of Lucii. And the only one who can properly wield it is Noct, so we really don't have a choice.

Ignis: And with no assurance the Crystal can beat back the daemon hordes.

Y/N: Well, we have to at least try.

Gladiolus: Guess we'll find out the hard way. No turning back now, right?

Noctis nods and they begin to move, gazing at the broken train car in front of them. It was hanging off a rock, no telling when it would collapse.

Gladiolus: This thing could come down at any time...

Ignis: Let's be quick.

Noctis: C'mon, this way.

Y/N: Right behind ya.

Noctis begins to cross under the train car, it creaking slightly as it almost fell down. As Gladiolus, Y/N, and Ignis were about to cross under, it crashes down, separating the king and his Crownsguard.

Noctis: Hey! Ignis! Gladio! Y/N!

There was no response from them and daemons begin to appear. Since Noctis had no way of fighting back, he had to flee.

As he ran, he could hear Ardyn's voice, but he didn't know where it was coming from.

Ardyn: Look at you. All by your lonesome.

Noctis: You again. You know, for an imperial chancellor, you are one sick son of a bitch. Daemons...the hell do you want? Leave me alone!

Crossing through a broken down passenger car, he encounters more daemons, but Noctis was able to dodge them thanks to his warping powers. He then runs up some stairs to escape the daemons.

Noctis: This is getting out of hand.

Running through an open door, Noctis was panting as he searches for a place to hide. Going behind some boxes, he goes into his pockets and pulls out the Ring of Lucii. It was the only weapon he had left.

Hesitantly, he put it on. As he did, he starts to feel intense pain, as if his hand was being teared off. It soon stops as the Ring knew Noctis was of royal blood. Noctis clenches his fist as he could feel the power coming off of it, now coursing through him.

Noctis: The time has come.

Up ahead, Snaga daemons drop down from the rafters, growling as they spot the Crown Prince.

Noctis: How did they get in here?

He extends his hand, a bright magenta light emitting off the ring. Noctis absorbs the life energy of the Snaga, killing it as it adds to his own.

He then sees a giant structure ahead.

Noctis: Looks like it's connected below. Might be my ticket to the top.

The Crown Prince then sets off for the elevator, hoping to find a way deeper into the Keep.

With Y/N, Gladiolus, and Ignis

After the passenger car had fell and separated them from their liege, Gladiolus helps the Sword and Hand up top. Y/N then extends his hand for Gladiolus so he could climb on top as well.

Ignis: Is there a way forward?

Y/N: Well, there is a way.

Gladiolus: But I don't think it going forward without facing off with the daemons.

Y/N: Noct must have fled. Probably didn't have enough time to put on the ring.

Ignis: Yes. Now, Noct is facing them alone. There must be some way we can help him.

???: Perhaps I could be of service?

They were startled as they looked to the voice. It was Ardyn, wearing a fedora as he stood at the entrance of a passenger car with a grin plastered on his face.

Gladiolus: What are you doing here?

Ardyn: (chuckles) Why I come bearing gifts.

Snapping his fingers, the weapons of the Hand, Shield, and Sword appear in their hands.

Y/N: What the...

Gladiolus: The hell?

Ardyn: See? Gifts. Now I believe a thank you is enough.

Y/N: To hell with that.

Gladiolus: For what? Enough for one of your stupid tricks?

Ardyn: Here I am helping for a change, but I can see I'm not wanted.

Ardyn walks away and Ignis walks up to the two.

Ignis: I'm loathe to trust him.

Gladiolus: Same.

Y/N: But at this point, we'll need all the help we can get. C'mon. Let's move.

Jumping down, Y/N helping Ignis down, they proceed through the same path Noctis had presumably went through, going through the broken down passenger car.

Ignis: I oughta have been more cautious. If anything were to happen to Noct.

Y/N: Hey, don't blame yourself. We didn't know that would happen.

Gladiolus: He's right. We can't move forward if you're always looking backwards. Quit thinking about what you could've done then and start thinking about what you can do now.

Ignis: (sigh) You're right. What's done is done.

Upon getting out of the passenger car, the see goblin daemons walking around the area. Since stealth wasn't an option, they engage.

Using his powerful greatsword, Gladiolus swings it with sheer force, getting rid of the daemons that stood in his way. Y/N with his quick speed used Hagekure, using iai technique, he drew his katana with great speed, sheathing it quickly as he finishes his slashes.

Ignis dodges any that came his way and used his polearm to keep them away. Ending their weak foes, they proceed forward.

Gladiolus: So if we can conjure our weapons again, does that mean Noct can too?

Ignis: I have a feeling the chancellor isn't so generous.

Gladiolus: How come?

Y/N: He may have feigned friendship, but he has proven to be a foe before.

Ignis: We'd best be careful.

They proceed down the route that Noctis had presumably went through. They enter a room and found an open hallway, one of the walls being broken down. Going through the hole, they find a radio.

Newscaster: (on radio) This is the imperial security bureau. A situation as risen in several research sectors. All civilians must relocate to their designated rescue stations immediately. Failure to evacuate will result in incarceration or other appropriate disciplinary procedures. This emergency broadcast will repeat until the situation has been resolved. The imperial security bureau thanks you for your cooperation.

Gladiolus: You think that situation is us or something else?

Ignis: The latter I presume. Whatever it is must be a matter of considerable scale to warrant such a warning.

Y/N: Well, I don't want to stick around to find out.

Ignis: Keep your ears open. These broadcasts might help us understand what's going on outside.

Going down through various hallways, they soon find an elevator. The elevator goes down and they wait a few minutes. The doors soon open to a hallway, but there were no guards or magitek troopers anywhere.

Ignis: It's dead silent.

Gladiolus: More like undead silent. 

Y/N: Strange. I don't see a single MT.

Gladiolus: But the place is crawling with daemons.

They run down the corridor, about to turn down another when Ardyn calls out to them.

Ardyn: Right this way, gentlemen.

Y/N: Where the hell is he?

Ignis: I don't know. Proceed with caution.

They walk down the hallway, listening to Ardyn's instructions, but were skeptical about it.

Ardyn: Keep going a little closer.

They stop in front of a wall that had a letter and numbers. A-00.

Ardyn: Here. That's a good boy.

It then starts to open, Gladiolus extending his arm out for Y/N and Ignis to stop.

Gladiolus: Hold up.

Y/N: What is it? Daemons?

Gladiolus: Well, found some kind of secret passage.

Ignis: Led here by our guide.

Y/N: Think Ardyn is trying to lead us to Noct or Prompto?

Gladiolus: Long as it's a step in the right direction, I'll take it.

Ignis: Where are we now?

Gladiolus: Where ever it is, it's a mess. Watch your step.

Y/N: There's a lot of shit on the floor. Guess they were leaving in a hurry.

They then find another radio when moving into the next room. Gladiolus presses the "play" button to play it's broadcast.

Newscaster: (on radio) This is a status report from the imperial defense force. The daemon outbreak coming from several research facilities have been suppressed in most areas. Magitek infantry units have been deployed in remaining sectors. The situation is under control. For your safety, a temporary curfew is imposed on all city areas. Your cooperation is required to ensure the security of yourself and other civilians. This broadcast will repeat until the curfew has been lifted and order has been restored.

Gladiolus: They've got their hands full.

Y/N: A daemon outbreak. That explains why they're running around all over the facility.

Gladiolus: Thought their little pets wouldn't break out of their little cages.

Ignis: I doubt even the daemons could simply escape from such a secure facility. It's more likely their master set them free.

Y/N: God damn, Aldercapt is one fucked up son of a bitch.

The broadcast then ended, the three of them proceeding through the facility as they battle their way through the various daemons.

Along the way, they encounter rogue magitek assassins, but they paid them no attention, causing the three Crownsguard members to be confused. But they continued along through the facility.

They then enter another room, which seemed to be a control room. In front of them were many monitors.

Gladiolus: Hey, guys. Think we might've found the control room.

Y/N: Well they do got a shit ton of monitors here.

Ignis: Which may help us monitor the rest of the keep.

Y/N: Hey, search for any of them to see if we can find Noct or Prompto in any of them.

Ignis: Does any of them look operable?

Y/N: They seem so.

Gladiolus: I'm more of a low-tech kind of guy, but we'll see what we can do.

Y/N: What's the...?

Gladiolus: Looks like they wiped everything.

Ignis: All of it!?

Gladiolus: Yup.

Y/N: Wait, there's somethin' here. It's a surveillance tape. I think they forgot to erase it. Not unless it was meant to be shown to us.

Ignis: Then we'd best have a look. Whatever's on that tape might help us locate Noct and Prompto.

Y/N presses play on the control panel, the monitor then showing the panel to the Shield and Sword while the advisor listened.

Iedolas: (video) What of the Hydraean's power? What of my precious ring?

Ravus: (video) By the hand of the Oracle, they are with the King now. Their rightful owner. And someday soon, they shall use it to purge our Star of it's Scourge.

Iedolas: (video) But the Crystal is mine. I am the one true King.

Ravus: (video) Nay. It is Noctis and none other.

In the video, a Necromancer daemon appears behind the older Fleuret.

Ravus: (video) Certainly not a puppet of the darkness and the daemons that are born.

Iedolas: (video) You are the puppet. And you must die.

Ravus begins to fight the daemons, but Iedolas uses some sort of dark magic, presumably from the Scourge, to push Ravus back. Ravus then falls over the railing, falling down to a lower level. The older Fleuret uses Regis's sword to help himself up, footsteps being heard.

It was Noctis.

Ravus: (video) At last you have arrived, Noctis. The gods have shown you their favor. As blood of the Oracle, I present you, your father's glaive. Now, go forth, my King. Shine your Light unto the world.

However, Noctis had summoned a copy of another Regis's sword, cutting Ravus down. This shocked the three that were watching. Noctis picks up the glaive and stabs it next to Ravus.

Noctis: (video) Spare me your sycophancy. I've indulged your false heroism far too long.

Then, Noctis's voice switches to Ardyn.

Ardyn: (video) You tried to save the world in my stead, but it wasn't enough. The Crystal chose me, not you.

Ardyn had been impersonating Noctis, making it look like the Lucian Prince was responsible for the murder of the High Commander.

The chancellor then digs into his coat and pulls out what seems to be messages, tossing it onto Ravus's lifeless corpse.

Ardyn: Aww, rejection hurts, doesn't it?

The video then ends.

Ignis: Was that, Noct?

Y/N: No.

Gladiolus: Just that scumbag chancellor posing as him.

Ignis: It sounded like Ravus was trying to return His Majesty's sword.

Y/N: Guess the asshole got over his grudge.

Gladiolus: Even called Noct his "King." Let's move. If that's what he did to Ravus, there's no telling what he'll do to Noct.

Y/N: And it looks like Ardyn bought himself some time.

Ignis: Then we've none to waste. We need to find Noct before he does.

Getting into the elevator that was in the room, they go up. They soon find themselves in a storage area.

Gladiolus: Hmm. Looks like some sort of cargo bay.

Ignis: Then there's a high probability the Crystal passed through here at some point in time. Is there a lift nearby they could have used to transport it?

Y/N: It's not here. Probably further up ahead.

Quickly battling through the daemons in the area, they find the lift they were looking for, having traversed a long way.

Entering, they descend down a level, going into a new area.

Ignis: We ought to be close to the core of the keep by now.

Y/N: This thing's a damn maze. That's probably where they're keeping the Crystal.

Ignis: And most likely where Noct is headed as we speak.

They traverse through a few more halls before coming into another room filled with monitors.

Gladiolus: Hey, there it is.

Ignis: What is it?

Y/N: The Crystal.

Gladiolus: Right here on the screen.

Ignis: Then we're close. Do you see any sort of control panel?

Gladiolus: Sure do.

Y/N goes to the control panel, messing with it to figure out Noctis's or Prompto's location. Ignis had went and stood behind Y/N and Gladiolus goes to the doors, securing the area and making sure no daemons come near them.

Ignis: If it's anything like the Citadel, there should be a barrier barring access.

Y/N: Then we unbar it. Tell me what to do, Iggy.

Ignis: Right.

After flicking different switches and pressing buttons, they deactivate the security measures on the Crystal.

A loud thud was heard and the three of them turn around, coming face-to-face with a daemon like no other. One they haven't see before.

What shocked them most was that it spoke to them.

???: Thieves cannot escape the hand of justice!

Y/N: What the fuck...

???: The Crystal is mine...never shall I lose my grip! The Crystal, the Light, the power...all of it...mine!

It then reveals a face, revealing the monster to be Iedolas Aldercapt, the emperor of Niflheim.

The daemon then charges at them, Y/N rolling out of the was as Gladiolus pushes Ignis. Summoning his one-handed sword, Y/N rushes forward with his Flame Art, Flare Blade, doing moderate damage. Summoning Hagekure, he uses both of his swords to parry the scythes on the creature. Gladiolus runs forward, summoning his shield as he rams into the beast, knocking it to the floor. Then summoning his two-handed sword, he performs his Glaive Art, Maelstrom, twisting and spinning as he does a flurry of blows.

The beast recovers quickly and roars in anger, Y/N kicking off the control panel of the monitors and latches onto the beast. Taking his sword, he starts to stab it repeatedly in it's side. However, the daemon then stabs one of it's scythes into Y/N, causing him to cry in pain as the daemon flings him to the side. Gladiolus goes to help, but the daemon had rushed at him and pushed him to the ground, the beast trying to use it's jaws to bite at him. Ignis uses his enhanced sense of hearing to throw an ice spell, freezing the beast for a short while. Supporting, Ignis throws an elixir at Y/N, the red haired male catching it as he crushes the potion, feeling revitalized.

The daemon then frees itself from it's ice prison, the daemon rushing at Y/N, but he came prepared. Y/N parries the attack, giving a quick strike with his katana. Then he uses Cor's signature technique, Lion's Roar. Sending a slice attack, he slices one of it's arm's off. Gladiolus then uses the Glaive Art, Dawnhammer, swinging his greatsword down as he slices the other off. The beast then jumps back, it's fallen limbs now regenerating as it then covers itself with it's wings, a dark matter surrounding itself as it recedes into the ground.

Ignis: (pants) I can't hear it anymore. Is it dead?

Y/N: No...the bastard escaped.

Gladiolus: Thing just disappeared. Ain't never seen one that talked like that before.

Ignis: Nor one so fixated on the Crystal.

Gladiolus: I thought Aranea said the daemons were afraid of the Crystal.

Ignis: It may be like moth's to a flame--or it may be one of the empire's "alternative facts."

Y/N: That fucker had a face. Looked like Aldercapt.

Gladiolus: Whichever it is, that monster's still on the loose.

Ignis: And we need to find it before it finds Noct and Prompto.

Y/N: Then let's go.

Before they were about to leave, Ardyn's voice could be heard again.

Ardyn: Oh, dear. I can see the light fading from your friends' eyes.

Y/N: You sick bastard.

Gladiolus: (grunts) Hang in there, Noct.

They then run down the hall, opening the door in front of them.

Ardyn: Ah-ah. Wrong way.

Turning around, they walk back down the hall and find a strange red symbol on their right.

Ardyn: Keep going...a little closer...

The wall with the symbol then starts to open, the three of them heading down the hall, running at full speed, but fast enough that Ignis could catch up.

Ardyn: What's this? I think he's stopped breathing. Why don't you come and see for yourself?

They open another door and it seemed to be a rest area. Y/N and Gladiolus find another radio and turn it on.

Imperial Soldier: (on radio) Calling all frequencies--hey. Hey! Is anybody out there? ...Anybody who hasn't turned yet? Anybody? This is--no, forget it. What does it matter? Only a matter of time until I turn just like everybody else did. He was right. "Ain't long until the empire falls--and when she does, it'll hurt like a ton of bricks." Should've taken his advice and got out when I had the chance. Y'hear that, Callux? You were right. Go on--tell me, "I told you so." Sorry I won't be able to pick up my tab.

Gladiolus: Think anyone else heard that?

Ignis: Hmm. If they did, I suspect they're no longer human enough to sympathize.

Gladiolus: Whole place has gone to hell...

Y/N: And that'll probably happen to us if we remain here any longer.

Gladiolus: All the rest is probably just fake news.

Ignis: Assuming all of what we heard is true.

Before they go down the next hallway, the one to their left opened, revealing a new room.

Gladiolus: (crosses arms) If that son of a bitch even--

Ignis: Wait. Can't you hear that?

Y/N Hear what?

Ignis: Noct's voice. I heard it clear as day. This way--follow me!

Ignis takes off down the corridor. The two look at each other before they run after the advisor.

Gladiolus: Hey, wait up!

After running for a few more minutes, they hear his voice.

Noctis: (muffled) I've really gone and done it now.

Ignis: Noct, is that you?

Y/N: Noct! Hey! We're here!

Gladiolus: Hey! Noct! Can you hear us?

Noctis: (muffled) Ignis, Gladio, Y/N!

Ignis: Where are you!

Loud explosions were heard on another side of a wall.

Y/N: I think we found him.

Gladiolus: Let's hurry!

They soon find Noctis behind an electric door with no way out.

Gladiolus: Noct's in trouble!

Ignis: Gladio! Y/N! There ought to be a kill switch nearby--find it!

Gladiolus: How do you know that?

Ignis: I believe it's the reason we were brought here.

Y/N starts to frantically search around the room while Gladiolus was kicking the door. Y/N sees what he was doing and summons his sword, stabbing it into the wires. The electric doors shut off and Gladiolus pulls Noctis out.

Gladiolus: That was close.

Noctis: The hell'd you get here?

Gladiolus: You're welcome?

Noctis: Thanks.

Y/N: Any clue to where Prompto is?

Noctis: No, haven't found him yet.

Ignis: After we were separated, we received "help"--from the usual suspect.

Gladiolus: That bastard's playing with us. But at least we're together.

Ignis: All but one of us.

Y/N: Yeah. Let's go get him.