(Author's Note: I've been looking forward for this. Might add some crossover only in this story.)

Third Person's POV

The episode starts with Sayo, The Knight slashing through a green slime and the other members of Roselia cheering for her.

Yukina, Lisa, Ako, Rinko: We did it!

Yukina (Ako): I think we've gotten the hang of this.

Sayo (Lisa): Sure, but not as well as you, Minato-san.

Ako (Yukina): What do you mean?

Rinko (Sayo): The monster in this are aren't much of a challenge anymore.

Lisa (Rinko): Should we go somewhere else?

Yukina (Ako): Then let's fight the stronger monster in the cave!

Aether: Wait up!

The others gazed at the person who yelled at them. It was Aether, Amber, Venti and Barbara. The party from the game Genshin Impact.

Aether: We wanted to join you guys too.

Ako (Yukina): Why is that?

Amber: We're having a mission to clean up the cave, so we heard that you guys are going at there. So, we might as well join with you.

Venti: Don't worry, we'll be a great help!

Barbara: If there's any trouble, I'll get you patched up!

Sayo (Lisa): Sounds good. Alright, you can join.

???: Hold on! Stay wherever you are!

Another voice can be heard as it reveals two figures heading to them. They're actually from the nation of Hoshido who is also from Hoshidan's royal family. They are the party from Fire Emblem Fates.

Sakura: Yukina-san, allow us Hoshidan to join you!

Then, a person step forward as he showed himself.

Wolf (Y/N): And let us fight as one.

Said Wolf (Y/N) who is the swordmaster of a clan named Hoshido.

Yukina (Ako): Who are you two?

Sakura: My name is Sakura, the Shrine Maiden of Hoshido.

Wolf (Y/N): Greetings. My name is Wolf, the swordmaster of Hoshido.

Sakura: We have decided to help you guys out since the 5 of you Roselia are from Hoshido.

(Author's Note: This isn't canon which means that about Roselia is from Hoshido, I just made it up. So, don't trust me that much. This is just a fan canon.)

Lisa (Rinko): Alright then!

???: Hey, don't leave us here! Wait up!

A female voice can be heard as it turns out that the characters from Cyberdimension Neptunia was also in this game.

Yukina (Ako): And you guys are...?

Neptune: The name's Neptune. My class is a Paladin.

Noire: Noire, Class: Black Knight.

Blanc: Blanc, Class: Priest.

Vert: Vert, Class: Enchanter.

Yukina (Ako): Alright! The more people join, the merrier and stronger our group are!

Aether: Let's go!

Wolf (Y/N): I'm always ready!

Neptune: Don't waste more time! Get yourself moving!

Yukina (Ako): Teleportation!

Everyone except Ako: Yeah!

Then, all of the group from Fire Emblem Fates, Genshin Impact, Cyberdimension Neptunia and Neo Fantasy Online begin teleporting to the cave where there's even stronger enemies inside of there. However, Ako is the only one who aren't teleporting yet.

Ako (Yukina): Hm? Huh?

Lisa (Rinko): Warp! Warp!

Then, Ako begin teleporting along with them. Then, their silhouette with a loading circle can be seen on their body.

While waiting for Yukina and Lisa to finished loading, Sayo, Ako and Rinko was looking at the front of them. There's a lot of strong monsters inside of it. They saw a golem walking around.

Rinko (Y/N): So, we're going to fight that?

Wolf (Y/N): We'll be fine.

Venti: As long as we're together, nothing is unstoppable!

After a while, Yukina and Lisa finally finished loading as they arrived at the cave.

Yukina (Ako): That load took forever!

They looked at the front of them as they saw the others are already begin fighting them.

Yukina & Lisa: That's the floor boss!

Aether: The main boss, huh?

Yukina (Ako): What do we do?! That thing's crazy strong, Rin-rin!

Neptune: What else? Defeat the boss, of course!

Noire: Don't rush yet.

Blanc: Yeah, we don't know if the boss can one-shot us.

Vert: It looks like it doesn't, so we're just fine.

Lisa (Rinko): First, we need to regroup.

Blanc: Good idea! We need to discuss the perfect strategy!

Then, they begin running as they went to join with the others.

Lisa (Rinko): Hikawa-san! Take aggro!

Rinko (Sayo): I've got it!

Lisa (Rinko): No, wait!

However, it's too late as the boss went to deal damages to Rinko as she got knocked out from the attack.

Lisa (Rinko): Oh no! I'm so sorry, I'm so sorry!

Amber: How dare you! Baron Bunny!

She then threw the Baron Bunny to the boss as it exploded after a while, but... it did only a little damage to it.

Wolf (Y/N): What are you doing?!

Amber: I tried my best, okay?!

Yukina (Ako): Um... the warrior was... Lisa-nee, take aggro!

Sayo (Lisa): Sorry, sorry! I took it!

Said Sayo as she went to the golem boss as she let the boss deal damage to her. This causes Sayo's HP to drop a lot for every hit.

Yukina (Ako): Shield! Shield!

Aether: Oh no. If only I got Noelle or Zhongli into my party...

Wolf (Y/N): There's no time to worry about the others! Worry about your party instead!

Then, Yukina begin playing with her lyre as she chant some magical words.

Yukina (Ako): Sing, lyre, the twilight melody! Envelope these warriors, and... uh... Defense up!

Then, Lisa and Sayo's Defense increased as they got shining brown-ish lights on their body. Next up, Lisa went to chant some words to heal the damaged characters.

Lisa (Rinko): Goddess of water, heal their wounds.

Both of Sayo and Rinko's HP went increasing moderately as a green aura emanate around their body healing them up.

Barbara: Allow me to patch you up even more! Shining Miracle!

Then, some of the damaged character's HP went up even more until they've reached max HP.

Ako (Yukina): I've found a herb.

Yukina (Ako): Fight!

Blanc: Duh, what do you think we're doing right now?

Sakura: Why aren't our team work together so well?

Ako (Yukina): It seems my inventory's full.

Wolf (Y/N): Use some of the items, then!

Ako (Yukina): Should I throw out this Heretic's Staff?

Yukina (Ako): No! You can only get one of those ever!

Rinko (Sayo): Look out!

As the boss was about to smash Ako, a fireball can be seen blasting to the boss as it land a hard hit to the boss dealing massive damage. It turns out that Rinko is the one who sent the fireball.

Rinko (Sayo): You shall not pass to lay a finger on Roselia!

Yukina (Ako): Sayo-san!

Rinko (Sayo): I'm sorry. I'm not used to this position.

Amber: What are you talking about? You're so cool!

Aether: Now isn't the time to compliment the others! We got a boss to defeat!

Wolf (Y/N): Alright! Everyone, keep attacking!

Said Wolf as he was fighting the boss along with Venti who used his Elemental Burst.

Venti: Wind's Grand Ode!

He released an Anemo arrow to the boss as it deals some continuous Anemo damage to the boss quite much as Neptune and Noire went to dash their way to the boss and send a sword slash to it's body dealing massive damage.

Sakura: Take this!

Then, Sakura used her bow to also attack the boss as it deals moderate damage. The boss' HP can be seen decreasing slowly.

Yukina (Ako): All right! We're all here!

Then, everyone finally grouped up together as they prepared themselves to defeat the boss.

Ako (Yukina): We're going on offense this time.

Lisa (Rinko): Leave healing to me, Barbara, Sakura and Blanc!

Sayo (Lisa): Umm... I'm supposed to take aggro?

Aether: No...

Then, Aether readies his sword.

Aether: We will.

Wolf (Y/N): I'll show you my skills in swordsmanship as a swordmaster!

Venti: Let's show the boss who we are!

Amber: I'll prove to you that I'm not useless!

Ako (Yukina): Let's go.

Everyone: Yeah!

They then went to face the boss with bravery and encouragement in their heart. However... what happened next is shocking.

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Actually, the teamwork didn't go well. Rinko, Vert and Amber was attacking the boss slowly while Sayo, Aether, Neptune, Noire and Wolf keep getting hit by the boss' punch. For Venti, he just keep using his bows and arrows to attack the boss. Meanwhile for Ako, she was just holding the herb and the Heretic's Staff. Yukina, Lisa, Barbara, Blanc and Sakura was just shocked seeing this while their jaw dropped.

Neptune: Oww!! My bone!

Noire: Aaaaaahhhh!!

However, all of their promise was just an empty talk as they got knocked out by the golem boss as they fly away by only a single punch from the boss.

Everyone: This was never going to work!

Then, the screen shows "Game Over" popping out showing Yukina who got knocked out.

The camera zooms out to show Ako who were at the front of the computer. Ako then just froze at there as her jaw dropped.

It turns out that Roselia, Aether's party featuring Barbara, Amber and Venti, the CPU from Gamindustri and Wolf were playing Neo Fantasy Online together. There's also a mega collab between Genshin Impact, Cyberdimension Neptunia: 4 Goddesses Online and Fire Emblem Fates happening right now, explaining the reason why are the other characters from different franchise appeared in NFO together with Roselia.

Right now, they're taking a break at the lobby while Yukina, Sayo, Neptune, Blanc,

Ako: That was so fun!

Aether: But too bad, we lost.

Amber: Don't worry, there'll always be next time. So, don't be sad.

Barbara: Yeah! You learnt from experience, they say.

Venti: Ehe. Maybe we should go level up later.

(Y/N): We should.

Rinko: It was a different experience.

(Y/N): I had a lot of fun playing.

Said (Y/N) who was playing as Wolf the Swordmaster of Hoshido.

Sayo: Let's do it without exchanging characters next time.

Yukina: You asked for it.

Lisa just winked at the others while smiling.

Lisa: So we're playing again?

(Y/N): If so, then let me know. I'm always ready!

Neptune: Me too!

Vert: I'll be there if you need me.

Noire: I-It's not like I wanted to join you later or anything if you invite me.

Blanc: I don't know if I could make it to play with you since I might be busy.

(The end...)

(Ending song...)

(Post-credit scene...)

Right now, you, Yukina and Lisa are walking back to your home while having some fun chat together.

(Y/N): Ahhh... what a fun day.

Yukina: I know, right?

Lisa: Well, we're not really that good in video games since we're not really into those.

(Y/N): But, I do... I mean, Marina-san allowed me to play video games, but not too much because I still have other things that I need to do.

Yukina: Hehe, you really cared for Marina-san, huh (Y/N)-san?

(Y/N): Of course I do, but it doesn't mean that I shouldn't care for you girls too.

As you said that, they stopped walking and you did the same.

Lisa: Wait... what? You also care for us?

(Y/N): Yeah, I do. You girls got your own personalities that attract me. That's what makes me care of you instead of just Marina all of the time.

Yukina: Is that so? Well, thank you.

(Y/N): You're welcome.

Then, both of Yukina and Lisa gazed at each other as you were confused of what will they do next.

(Y/N): W-What are you doing?

Lisa: Just stand still~

Both of Yukina and Lisa went to kiss your cheek as you blushed. After a while, they stopped kissing and smiled at you.

(Y/N): W-Why did you do that all of a sudden?!

Lisa: Hehe, you're so cute when getting teased, (Y/N)-kun~

Yukina: Lisa's right.

(Y/N): L-Let's just go home already.

Yukina & Lisa: Let's.

Then, the three of you continue heading back to your home as you bid goodnight to Yukina and Lisa.

(Y/N): I'm having my own harem, huh? Just like those main character from those harem anime. I like it.

(Author's Note: Shout-out to HoshidanWolf for recommending his OC, Wolf into this chapter. I appreciate it. If you guys want to, you can message me in Discord and suggest your OC to make ONLY one chapter. With that being said, I'll catch you all in the next one.)