The search for Kellogg continues with Dogmeat tracking areas where Kellogg once was. Again and again, Dogmeat found only a known location where Kellogg was, then force to catch another scent there in order to continue the search. They would have to travel a long distance in order to reach their destination, but Doomguy desire to continue this until Dogmeat found the main location.

During the travel across the old railway, they engage a couple of feral dogs and a large bear, then a couple of ghouls hiding underneath the broken train carriages. They found more ghouls when running across the bridge to catch up with Dogmeat, there they hear he was getting angry at the scent of ghouls crawling out from underneath the vehicles and force them to shoot them all dead. More ghouls would hear the gunfire from where they hide, so they came out from a nearby building on the other side of the bridge and force them to waste more ammo on killing them off. This is also the time where Doomguy encounters the Super Mutants for the first time, and one of them was carrying a serious bomb that could wipe them if they got too close. Thankfully, Sonja fires a lucky shot that causes the explosion to wipe them out with just one bullet.

"Those weren't ghouls…" Doomguy mutters when seeing only a few seconds of the Super Mutants in the distance, before they got blown to pieces by Sonja.

"They're Super Mutants. You met one of them before, except he was completely huge and you decided to punch it in the face." Sonja replies and made him remember his fight with the behemoth.

"Oh…."

"You punched a behemoth?!" Piper asks and scoffs at hearing that

Sonja looks to her and responds "I know right."

"Well… That's believable because he did punched a man wearing a power armour." Piper replies

"He's insane. I like insane guys." Sonja replies

"And he's married, in case you've forgotten about that."

"She must be one hell of a woman."

"Yeah… She is…" Doomguy replies and continues walking further ahead.

Dogmeat catches the scent yet again from broken robots they found further ahead from the explosion they cause. Sonja scavenges the material and medical items first before advancing further ahead. They were getting closer to Kellogg, and found themselves almost coming face to face with a Deathclaw in the area. Thankfully, the team found the Deathclaw on the road and already dead with parts of its body torn off.

"A Deathclaw…" Sonja replies when moving around the body to see the damage done to it "Looks like it didn't stand a chance."

"But what killed it?" Piper asks and looks around the area with her weapon at the ready to pull the trigger.

Doomguy stares down at the dead Deathclaw, suddenly causing a flashback of a moment where he stood down at a dead Baron of Hell. He tore that thing apart with the BFG-9000. This made him get a slight headache and turns away with his left hand pressing against his forehead.

"It's possible a stronger Deathclaw killed it. We need to look –" Sonja stops when she looks towards Doomguy to see him not well "Hey, don't you go passing out on us."

Doomguy sighs and shakes his head. He looks back at her and replies "I'm fine."

And so they continue forward with Dogmeat still leading them to their final destination. Doomguy arms the minigun at the ready, knowing whatever tore through the Deathclaw is still somewhere around here. He looks at his minigun and thought to himself "I'm going to need more than this…"

And as they continue on ahead, everyone stops at the sudden sound of a terrifying roar in the distance. Dogmeat would start to growl and starts barking at something in the distance, which causes the monster to turn its attention towards them. Sonja rushes over to try to silent Dogmeat, knowing his barking could attract the attention.

"What was that? Another Deathclaw?" Piper asks and looks around the area quickly with fear in her eyes. She did not wish for this creature to sneak up on them and attack from behind. When she looks back at Doomguy, he was left standing there with surprise look on his face because he recognises that roar.

"That's no Deathclaw…."

Sonja takes control of Dogmeat and brings him back with the others, knowing the enemy is coming towards them. As she moves away, she looks back when Piper calls out "I see it…. Oh my god!" And Sonja looks to where Piper was looking. She could see this monstrosity approaching them through the darkness towards them.

While the three starts moving backwards to retreat, Doomguy remains standing where he was and looking straight at the incoming enemy approaching them. The moment he heard that roar, he knew what it was coming towards them. He always knew he would one day face them again, and now one presents itself straight towards him. He would either fight them in his nightmares or fight them in the real world.

Out of the shadows was a Baron of Hell, one of Hell's greatest warriors. The red Baron was a sight to bring fear to anyone that even sees it, but Doomguy remains where he stands with his minigun ready to fire. One thing he starts to notice was the Baron had a serious modification towards the left arm and leg and half the head with serious cybernetic augmentation. The Cyber-Baron stops and scans Doomguy with its cybernetic eye, which causes so many 'Danger' signs to appear on its screen. That Baron knew exactly who he was because it barely survive the last time it once try to engage Doomguy in combat.

Doomguy finally spins up the minigun and holds down the trigger. The Baron ignores the bullets and runs straight towards him, then swings both arms down at him when it was close enough to crush him. Doomguy would jump to the side, continues firing his gun until he ran out of ammo. Sonja and Piper came in to support Doomguy by catching the Baron's attention by firing against it. The Baron ignores the bullets and claws Doomguy to the chest to knock him to the floor, and destroying his minigun in the process. Before the Baron could continue with him, it charges a green fireball from its right claw and swings underarm towards Piper. She did get out of the way on time and witness the green fireball flying just past her right shoulder. The two continues firing their guns, but the Baron focuses on Doomguy only.

With only an axe in his arsenal, Doomguy was left to fight this Baron at close range with the axe, and trying to avoid any more of those claws. Unfortunately, he lost the axe and attacks the Baron by punching the right knee with a strong punch, which was enough to deliver some damage to the bone to cause the Baron to suffer in pain over it. The Baron responds by hitting him at close range with the green fireball to the chest, instantly destroying his armour and giving him a serious burn across the front of his body. He cries out in agony over the flames, but his rage continues to fight and proceeds to keep punching the Baron.

After being knock back to the floor, the Baron turns towards the others and decide to chase after them. They kept firing until they finally ran out of ammo, then force to make a run for it when the Baron turns towards them. It was pretty fast to easily catch up to them and sends Sonja flying with just a hit from its mechanical arm, then releases a green fireball from the other arm to target Piper in the back.

Doomguy rises back up and looks back at the Baron "Hey…. Where do you think you're going?" He whispers in an angry tone and runs towards the Baron to save the two. Ignoring the injuries on his body, Doomguy shows he still has enough stamina to sprint straight towards the Baron and targets the leg a second time. When the Baron turns to the side to look back at him, Doomguy punches the side of the knee and finally does enough damage to bring the Baron down to one knee. After it was down and weaken, he finishes it by grabbing onto one of its horns with both hands, ripped the whole horn right off the head and drives the point straight through the face.

Dogmeat runs over towards Sonja to see she was okay, and she rises up off the ground and moans over the damage she took from that hit. She joins Piper and walk towards the front of the Baron to get a good view of this dead thing. Doomguy remain standing with serious burns and marks on his body, but he remains standing and ignoring the damage done to him. As soon as Sonja uses a stimpak on herself, she gives Doomguy one to help with the injuries.

"Holy shit…." Piper replies when looking at the head of the dead Baron.

"I was going to say the same thing." Sonja replies and comes towards Doomguy to offer a stimpak to him "And you look terrible."

Doomguy takes the stimpak and replies "I've had worse…"

"Okay, there's seriously something wrong with you." Sonja replies. She looks back at the dead Baron and continues "I've never seen anything quite like this before, and I've been all across this wasteland. Is that actually a demon?"

"Like the picture…" Piper mutters and thinks about that comic she shown Doomguy back at Diamond City. She looks back to Doomguy and says to him "You're him. The man on the cover, aren't you?"

"Yes."

Piper scoffs and smirks when saying "The Doom Marine. That's you."

"What? You're…." Sonja looks to him and he looks back at her. She starts to laugh a bit and replies "I don't believe this…"

"Never thought that story you told me was actually true. You fought these things at your time?" Piper asks

"Yes." Doomguy walks closer to the Baron and stomps his right foot against the head "And I won."

"Wait, wait, wait… You're telling me you're actually the so called 'Doom Marine'? From the stories?" Sonja asks him

"Yes."

"You heard from it too?" Piper asks her

"Well, yes, but didn't expect them to be true. My mother told me of such tales. And there was that rumour talking about a man wearing green armour claims to be the incarnation of that said Doom Marine. He's hanging out with the Gunners." Sonja looks to Doomguy "Maybe he's a friend of yours?"

Doomguy turns away from the dead Baron and looks back to Dogmeat "Can your friend still track Kellogg?"

"You still want to go after him?" Piper asks "We don't have any ammo."

"Hmmm, wasn't really smart for me to ask you to get rid of your guns and ammo…" Sonja shakes her head and sighs

"I'll handle it. There's still a chance for you to return home." Doomguy looks to Piper

"I could… I did promise to come with you. Can't leave this half-finished."

"Agreed. And with those muscular arms of yours, it'll be much easy to get more ammo off the bodies of your victims." Sonja replies

"Alright. Let's go."

And so the search goes on track with Dogmeat leading them away from the dead Baron and continuing the search for Kellogg. With no sign of any resistance in their way, Dogmeat finally sent the team towards Fort Hagen. They notice active turrets are on the roof, but they avoid getting caught by them when following Dogmeat to a dead end door.

"This must be the place." Sonja replies and starts patting Dogmeat "You're such a good friend."

"So what is the plan when you do find Kellogg?" Piper asks him

"You can't really kill him when you see him." Sonja looks back to Doomguy

"I'll make sure he talks. We need another entrance."

"There's probably another entrance elsewhere. Let's check the area and avoid getting hit by the turrets." Sonja replies and takes the lead with Dogmeat following her

The team moves to the garage area to find a doorway leading to the interior of the fort. As they enter through the garage, they move up the stairs and wait for a moment when hearing the sound of footsteps and hearing voices from a synth. They choose to remain hiding behind corners in an attempt to surprise them and catch them off guard. Doomguy caught one of them, grabs onto its head and easily twists it enough to rip the whole head off of it. He then use the body as a shield to avoid damage from a second synth firing its laser rifle, then throws the body towards the synth and crushes its head with his bare hands.

"Now we have weapons." Sonja replies and takes both the laser rifles and offers the second to Piper.

"Not much ammo in these."

"It's a start." Sonja looks back to Doomguy "Want to keep doing that?"

"Yeah." Doomguy faces forward and proceed up ahead to search for the other nearby synths in the area.

Doomguy took a few hits to the chest with rounds from a laser rifle, but it was enough to get close enough to rip through these synths and take their weapons off of them. He offers the ammo to both Sonja and Piper to give them a better chance, while continuing to ignore the damage.

"That body of yours can't take all of those hits…" Sonja replies and moves to his right "Let me take point and you take a breather." She then moves forward with her laser rifle at the ready and eventually firing at an incoming synth with a melee weapon.

Piper comes to Doomguy and offers him a stimpak "This is the last one I got. You need it more than me." Then follows Sonja when Doomguy takes the stimpak off of her.

Doomguy uses the stimpak to replenish at full health again, then follows them from behind and leave the fighting to them for the time being.

Meanwhile, inside the main command centre, Kellogg was busy on the terminal and hearing from the synths about intruders have arrive. He gives the synths around him some orders and decide to go inside his power armour for better protection of what is coming his way.

After gunning their way through the interior, they eventually arrive inside the command centre, there they would hear Kellogg calling out to them through the speakers of the interior to communicate with them.

"Hmph. Never expected you to come knocking on my door. Gave you 50/50 odds of making it to Diamond City. After that? Figured the Commonwealth would chew you up like jerky."

"This guy has no idea who he's messing with." Sonja replies and continues moving forward

"That's the voice…" Doomguy replies and tightens the grip of his laser rifle "He's the one."

"Take it easy, blue. We haven't found him yet." Piper replies

"But he's here. I will get him."

Kellogg communicates with them again by saying "Look. You're pissed off. I get it. I do. But whatever you hope to accomplish in here? It is not going to go your way."

Doomguy continues pushing forward and helps annihilate the rest of the defending synths standing in their way. As they continue, Sonja decides to take a detour and found a hidden armoury that contains so many ammo for their laser rifles, as well as an actual Fat Man with to mini nukes. The moment she try to lock pick the door, Doomguy decides to help her and easily kicks the door off the hinges pretty easy.

Sonja stops and laughs "You should try that to a master lock."

"He actually did." Piper replies and laughs too

Both Piper and Sonja takes the ammo for the laser rifle and Doomguy straight up takes the Fat Man for himself and a nearby pistol with an ammo of thirty rounds. He chooses to use the pistol and not wishing to use the Fat Man in an interior that could wipe everyone out.

"Try not to use that against Kellogg…." Sonja says to him

"I'm not using it." Doomguy replies and looks at the pistol "This will be enough."

"If you say so."

And so Doomguy continues the lead with his handgun and firing at more synths that continues standing in his way from reaching Kellogg. It was annoying, but nothing was going to stand in his way.

"Okay, you made it. I'm just up ahead. My synths are standing down. Let's talk."

At long last, Doomguy would finally reach the end of this place where Kellogg is hiding, there they find him with a few synths standing by and waiting for the attackers to arrive in the room to see each other face to face. Kellogg came out in his power suit with his revolver in one hand and his helmet on the other.

"And there he is. The most resilient man in the Commonwealth. Hmmm, you look like you've been through hell."

"Been there, conquered it. Now, where are they?" Doomguy asks with an angry look on his face and the feeling to wish he could kill Kellogg right now like he was a demon in front of him

"As you can see, it's just all of us here. I'm afraid they're not even here." Kellogg replies "So you see? It is the end of the line. But not the way you imagined. But don't worry. You'll die knowing they're safe, and happy. A bit older than you expected, but ah well. At least they're both safe at home. The Institute."

"You've got to be kidding me… If they try to get in my way, they're going to lose."

"You're a persistent one. It's the way a parent should act. The way I'd be acting if I were in your place, I like to think. Even if it is useless. But I think we've been talking long enough. We both know how this has to end." Kellogg puts on his helmet and says to him "You ready?"

And just like that, Doomguy makes the first move by punching him across the face and actually sending him back a few steps from that serious punch. Kellogg attempt to use his revolver against him, but he grabs his arm to lift it high enough to fire his gun above his head, then proceeds to land a few punches against his armour and use his handgun to fire a dozen times against the chest plate to try to pierce through the armour.

While the two fight, Piper and Sonja quickly move into cover and starts firing at the other synths in the room. Dogmeat interferes against one and tackles it to the ground, which gives Sonja a chance to step in and fire a few shots through the head, then calls Dogmeat again to hide when another synth fires.

Doomguy lands a few blows against Kellogg, while he continues throwing him around and throwing him through one of the heavy doors, and somehow he still rises back up to continue.

"What is this guy?" Kellogg asks himself and quickly defends himself when Doomguy charges "No matter what I do… He keeps coming."

Doomguy takes another blow to the face, but it only made him lean his head back and leaves just a bruise. He counters by swinging his right arm against the belly of the power armour and succeed in actually damaging the armour. Kellogg takes a few steps back when noticing his armour is badly damage by some of his attacks, so he decides to activate one of the abilities to make his entire power armour invisible. Doomguy stops for a moment to find he was completely invisible for him to not be able to see him at all. Although, this was not the first time he fought someone that has the power of invisibility, so the only option was to prepare himself to take a hit and then try to counter by hitting back harder.

However, Sonja chose to intervene in this fight by throwing a pule grenade she stole from a dead synth and cause an electric burst to make Kellogg visible for Doomguy to see. As soon as he saw him, Sonja threw Kellogg's revolver she took off the ground towards Doomguy and allow him to fire a single shot towards the broken chest piece, which was enough to penetrate through it and leave that bullet stuck inside his body.

Kellogg drops down to his knees when feeling the bullet go into his body. Doomguy comes up to him to rip the helmet off the suit and throw it to the floor. He grabs him by the neck and tightens the grip in rage towards Kellogg. Kellogg simply smiles to him and responds "… You're pissed…"

Doomguy presses the revolver against his face and replies "You put this gun to her face. You were going to kill her."

"You should thank Hayden for that." Kellogg coughs out blood and falls to the side to collapse on the floor. The last thing he says to him was "Good luck finding them..."

Doomguy steps closer to him and fires another shot through his head to finish him off. At long last, Kellogg dies at the hands of Doomguy by his own gun.

"Hey, we could've kept him to interrogate." Sonja replies

"No." Doomguy replies and keeps staring down at Kellogg "I finished it."

"So the kidnapper gets his brains blown out by an avenging parent." Piper replies and sighs "It'd be a great ending if we didn't still have the biggest mystery in the Commonwealth to solve…"

"He said Hayden…" Doomguy looks to Sonja "Heard of him?"

"Hayden? He's actually the man in charge of the UAC and the ARC. I've never actually met the man before, so if Kellogg mentioned about him looking for your family…."

"It could be to get you off track." Piper replies "What do we know so far? Kellogg said both your son and wife is with the Institute. If this 'Hayden' is something about the Institute –"

"That's my next target. How do I get into the UAC?"

"You have to go through the ARC." Sonja replies "And before you even ask, I can't do it. It was hard for me to get myself out of the ARC, and no way am I going back in there. They'll definitely kill me for sure. And after everything we've been through, and almost getting ourselves killed, I need some time of relaxation from this place."

"Thanks." Doomguy says to her and offers her the revolver.

"You take it. You'll be needing a lot of firepower if you want to take on the Institute, the UAC and the ARC." Sonja turns away and takes her leave from the room.

Piper turns her attention towards the clean white table in the room with a white terminal on it. She came over to check to find anything valuable she could take from the table and check the terminal to find anything useful they could find. After finding nothing on the terminal, the three would depart from this place together and takes the elevator to the roof.

The three are in the clear, they arrive outside on the roof and found a new visitor arriving in the Commonwealth. High in the sky was a sight to see as an airship comes flying in with a few helicopters flying beside it with the means of starting an all-out war against the Institute.

"People of the Commonwealth; do not interfere. Our intentions are peaceful. We are the Brotherhood of Steel."