Sirin was sitting over the castle bridge gate a day after assisting Ainz with his Battle with Baharut empire she musing to herself some tunes. Though she was wondering where Ainz and his Marry band had disappeared.

"Sirin-Sama." Came the voice of her precious pet Bella as she glided onto her.

"What is it Bella?" Sirin asked the dragon girl.

"I found a strange button on the doorstep, I thought you would be interested in it." Bella told Sirin as she showed Sirin a strange blue colored box shaped object with a big red button in the middle of it.

"Could it be from the empire or any other faction?" Sirin asked eternal companion.

"I don't believe that any of the Kingdoms or Empires in this world have the level of sophistication  to make such construct and they aren't anything can make machines other than Ainz's Automaton maid." Bella told Sirin the later whom grabbed the button and gave it a look.

"Well let's press it and see what happens?" Sirin asked Bella as she pressed the button.

In a School 4 groups were standing in a class room

"Does anyone know what's happening? Why haven't we started the lesson already?" Asked the guy wearing a green cape.

"Be patient Kazuma." Said the Blue haired girl sitting next to Kazuma.

"Aqua..... No one asked you." Kazuma told Aqua who gave a Nasty glare.

"Alright everyone, sorry for the delay. We had some new Studeeents." Said the Eccentric Professor, catching euveryons attention. 

"New students?" Everyone asked in sync.

"Sirin, Bella. You can come iiiin now." Said the Professor as the door slid open to show Sirin and Bella. many who didn't know the two looked at then with wonder and as for Ainz his group looked at the with opened mouths.

As the Two girls entered the classroom, Sirin introduced herself and Bella.

"Hello everyone name's Sirin and I'm the 1st Herrscher and this is my companion/friend Bella." Sirin Introduced herself as she rubbed her face with Bella's like a cat would making everyone sweatdrop with the acceptation the professor who continued smiling. 

"Hey Bonii-Chan." Bella waved at Ainz who returned the gesture.

"Hello Sirin." Ainz said calmly.

"How's Demiurge and his Auschwitz?" Sirin asked Ainz, the later who looked like a shocked Goose. 

With Tanya, Ainz and Sirin outside.

"So you are saying that you helped Ainz in a war with this Baharut Empire?" Tanya asked Sirin.

"Yes, and used my Gem of Reason to construct the Russian 420mm 2B1 Oka Artillery platforms" Sirin told Tanya.

"Man having powers like yours makes things easier. I wished I had them and then I would show that bastard Being X who was Boss." Tanya said.

"You must Really hate this Being X?" Ainz told Tanya.

"Who wouldn't hate the Lazy good for nothing god wannabe." Tanya answered Ainz's question.

"True."  Ainz agreed with Tanya.

"Say Tanya wouldn't you like to be a Herrscher?" Sirin asked Tanya.

"For real, but what's the catch there is always a catch?" Tanya asked Sirin skeptically  

"There is no catch and you will have enough power to raze your enemies asunder." Sirin told Tanya.

"So no catch, No need to make some prayer or something like that?" Tanya asked Sirin, if the deal was as good as it sounded.

"The only thing that it is needed is you will, and that's it. And who know you might get a pet Dragon like I did." Sirin told Tanya.

"I'm in. Being X I will gunning for you once all this is over" Tanya thought to herself as she accepted Sirin's deal.

Scene change 

It was the Talent Competition and it was Sirin's Turn.

"Alright I will begin. First off." Sirin said as she snapped her finger and some blue feather started falling which caused the members to fall asleep.   

"What happened?" Tanya asked as she regained her conscience only to find herself in an opera hall.

"Greetings everyone, I present you something I have been working for a while which I call it a War Orchestra. Please take your seats and enjoy." Sirin who was dressed in a composer suit said.

https://youtu.be/xZam5xuePH8

AN: Hope You lot Liked it. And Yes Herrscher Tanya will be a thing if I do that story