(A/N: I actually thought of this idea for a long time with different mechas until I settled with Shurouga and then decided to actually writing it)

Y/N is the well-respected and the most successful Commander in Azur Lane. Because of him, humanity successfully reclaimed most of their territories from the Sirens. He even married many shipgirls who loved him so much. Other commanders got jealous and tried to kill him and blamed it all on Sirens.

(Timeskip)

Y/N is seen getting shot at by his fellow commanders.

Y/N: Tch, you bastards! You won't get away with this!

Random Commander That No One Cares About 1: Yeah right. With you out of the way, your wives and other shipgirls will be ours!

Y/N: Hah! As if! They will never be tempted to get screwed by your ugly asses no matter how hard you try. They're not like some cheap whores you can get on the streets. They are WAY better than that.

Random Commander That No One Cares About 2: Shut up!

They then keep shooting Y/N until he's finally dead.

Random Commander That No One Cares About 3: After we throw his body to the ocean, the shipgirls soon will be ours!

(Timeskip)

Unfortunately for the traitors, none of the shipgirls are stupid enough to fall under their temptation especially after what they did to them.

The news of Y/N's death made the shipgirls especially Y/N's wives really sad because he was the only commander they can really trust because they absolutely hated the other commanders because they are really incompetent at their job as commanders making them wonder how the hell they can be the commanders in the first place and they got really sick of their perverted antics. Once they found out that these "commanders" were responsible for Y/N's death, High Command decided to leave the punishment to the shipgirls due to how close they are to Y/N and also because they don't like them either.

Random Commander That No One Cares About 4: Please don't kill us.

Akagi: Oh, don't worry, we won't kill you, not now anyway, because that will be an easy way out for you. We will give you something much MUCH worse instead.

As their punishment, the shipgirls made them their own punching bags, figuratively and sometimes literally, they were careful to not accidentally kill them and also not to forget to feed them sometimes so they can torture them even more and also to vent their anger on them.

(Timeskip)
One month after Y/N's death

One month later, a new commander arrived and the shipgirls were very skeptical of him and one of them volunteered to watch over him without him knowing.
Several days later, she found out that he planned to drug and rape Y/N's wives until they forget about him and she immediately put a stop to his plan and tell the others about it. To say they were angry was an understatement. After they reported this commander to High Command. They put him in the same torture room as the traitors and give him the same treatment as them.

(Timeskip)
Three months after Y/N's death

The shipgirls currently having a hard time against the Sirens that are more powerful than usual.

Enterprise: Damnit, the Sirens are somehow stronger than before, if this keep on going we will be wiped out soon.

Belfast: I'm afraid you are correct Lady Enterprise, but we have to defeat them with all of our might if we want to have a better future.

Enterprise: Everyone! Don't give up!

On the other side of the battlefield, Purifier is seen laughing at the shipgirls' struggle.

Purifier: HAHAHAHA! It's useless Azur LAME, you guys are doomed, you can't beat us without your precious commander Y/N, just give up and maybe I will give you guys a painless death.

Enterprise: NO! We won't give up, we will defend the seas from you in honor of our late commander and husband, Y/N.

Purifier: Fine then, have it your way.

She and the other sirens then launch their missiles at the shipgirls which injured most of them.

Arbiter The Empress III: Looks like this is it then, goodbye Azur Lane.

Just as the Sirens about to deal the finishing blow, something fast wiped out some of their ships.

Arbiter: What!? What was that!?

A black Mecha suddenly appeared on the battlefield, surprising everyone there.

Arbiter: Ugh, what is that thing? That thing doesn't exist in the database. Everyone! Attack that robot!

The Sirens try to attack the mysterious mecha only for it to intercept their attack with ease.

???: I have arrived, is this really the correct one? I see the shipgirls and the Sirens but this is not the only world with them in it so I need to be sure.

The Mecha then scans its surrounding to confirm its pilot's question.

???: This IS the one! HAHAHAHA! I'M BACK! I'M FINALLY BACK!

The yell from the mysterious black mecha shocked everyone especially the shipgirls because the voice sounds eerily similar to the late commander Y/N. But that can't be him, right?

Enterprise: T-that voice...

Akagi: Shikikan-sama?

Belfast: Master?

Y/N: Attention to all shipgirls, this is Y/N L/N speaking, I'm currently piloting Shurouga Sin, the black Mecha you see right now, I know all of you have a question right now, but we have Sirens to take care of.

Enterprise: Y/N?

Y/N: Let's go, Shurouga Sin!

https://www.youtube.com/watch?v=Pux5-4x72EE

Purifier: Uhh, why do I hear a boss music?

Y/N's Shurouga Sin then summons several prana circles which then summoned many black dragon-like creatures that tears the Sirens' fleets apart so easily just by flying through them.

The Sirens try to attack him again but he just dodges them slashes some of them in return.

Shurouga Sin then starts changing its sword, Discalibur, from a long sword to a large broadsword and assumes the Sunrise Stance.

And then he flies towards the Sirens' fleets at high speed and cleaves any Sirens' ships and planes in his way.

Roon: Woow...

Tirpitz: So fast...

After that, he goes to the remaining
Sirens' fleets and yells...

Y/N: EMBRACE THE INFERNO!

Shurouga Sin releasing its power, destroying almost every Sirens except for Purifier, Observer, and Arbiter.

Observer: Damnit! I tried to find out more about that mecha yet I found nothing about it.

Shurouga Sin then charges at them at high speed and grabs them to the air before rapidly slash them while also laughing maniacally.

Y/N: Hahaha! Hahahahaha!!

Enterprise: Y-Y/N?

And creating a black magic circle in the sky which then explode with them in the center of it, killing them.

Y/N: Now that the Sirens are finally gone...

Enterprise: Y/N? Is that really you?

Y/N then sees the shipgirls approaching him.

Y/N: Yes, Enty. It is indeed me, if you still not sure, then I can tell you about what you did with my unifo-

Enterprise: [blushes] Alright, alright! It's really you! [Confused] But how?

Y/N: [Chuckles] Long story. But I need to land this mecha first.

Enterprise then summons a mass production version of her ship.

Enterprise: You can land it there.

Y/N: Thank you, Enty.

(Timeskip)

As Y/N lands his mecha, he saw the shipgirls approaching him.

After he got off Shurouga Sin, he immediately got tackled and hugged by some of his wives that were present during the battle.

"Y/N!"

Y/N: Oof! Whoa!

Enterprise: [hugging Y/N] We missed you so much, Y/N. We thought those bastards killed you.

Atago: [also hugging Y/N] Onee-san missed you too, Y/N~

Akagi: [also hugging Y/N] Akagi missed you soo much, Shikikan-sama~ Akagi missed your presence, your touch, your smile, your smell, your everything!

Y/N: [Hugs them back] I missed you girls too.

Belfast: Master, May I ask a question?

Y/N: Sure, ask away.

Belfast: How are you still alive? Those bastards killed you and blamed the Sirens for your death.

Y/N: Hmm, you know what? I would rather answer that question in HQ where many other shipgirls can hear my answer.

Belfast: I understand, master.

Belfast then join the girls hugging Y/N.

Belfast: I miss you so much, mast- no, Y/N~

Y/N: [Pat Belfast's head] I missed you too, Bel. It's been years, hasn't it?

Girls: YEARS?!

Enterprise: What do you mean years? You have been dead for three months!

Y/N: Three months, huh.

Y/N: Anyway, How are things going on Azur Lane when I was gone?

Jean Bart: Terrible. Those good for nothing "commanders" were getting worse after your death. They kept trying to make us fall under their temptation and make us theirs after your death. There's no way we want to have anything to do with those assholes, especially after what they did to us. Only dumbasses would fall in love with them. Once we found out that those bastards were responsible for your death, the High Command let us decide the punishment for them and we decided to made them our punching bags figuratively and sometimes literally so we can torture them for killing you and to vent our anger on them and also because immediately killing them would be an easy way out for them. We can bring you to them so you can have a "touching reunion" with them.

Y/N: O-Okay... (Damn, I knew they would be pissed off when they finally found out about who actually caused my death but not THIS pissed off)

Bismarck Zwei then adds...

Bismarck Zwei: That's not all, a month after your death, a commander that was supposed to be your replacement planned to drug and rape us until we forget about you.

Y/N: WHAT?! Do you know where he is? I want to "talk" with him.

Bismarck Zwei: Oh, you don't need to worry about him. We put them in the same room as those scums, so you can do whatever you want with him after your "reunion" with them.

(Timeskip)

The shipgirls that stayed at HQ to guard the place are quite surprised by the giant robot that was parked at Enterprise's mass production ship.

"What is that thing?"

"Whoa! A giant robot!"

"Is that a Sirens' weapon that they captured?"

They are even more surprised when they see Y/N get off the ship after Enterprise.

"Y/N?!"

"Commander Y/N?!"

"He's still alive!"

"But how?"

Y/N: Hey, girls.

"COMMANDER!"

"SHIKIKAN!"

"KOMMANDANT!"

"MASTER!"

"Y/N!"

"YOU'RE ALIVE!"

Y/N gets tackled and hugged again by more shipgirls who missed him.

Y/N: Oof! [Pats each of their head] It's fine girls, I won't leave you all again.

Sirius: How are you still alive, my honorable Master? Those scums said they shot you and throw your body at the ocean.

Y/N: It's a long story, but I can tell you all some of my favorite parts of my journey throughout the multiverse.

Enterprise: Multiverse? You mean the multiverse is real?

Y/N: Yup! I'll tell you more about it after you tend your injuries and after all the shipgirls gather here. Those assholes can wait.

(A/N: This story originally gonna be a one-shot story with a really simple plot with that being: Y/N arrives -> He saves them from defeat -> he reunites with them -> beat up the traitors that were held in torture room by the shipgirls -> probably some lemon scenes -> the end. But I keep getting more ideas for this story while writing my Genm story)

(A/N: Shurouga isn't the only choice that I thought of for this story. The other choices are Huckebein and a Getter Robo (preferably Black Getter (Daikessen ver.) or Shin Getter Robo Tarak))

(A/N: Anyway, here's some bnuuy and other images I find cool and funny)

(A/N: Not mine, I found this picture on Facebook long ago, I forgot where exactly. Destiny looks cool with Strike Freedom's colors not gonna lie)

(Here, some choccy milk. Because you're epic)