Reena, a young woman with long white hair and dark eyes, frowned as she looked at the Archon hall. It was damaged, Hydro disappeared as the Gnosis shattered. What happened, she did not know. She needed to repair her home and realm but lacked the power. 

"Unless." 

a psychic pressure like a tidal wave shook the hall, and Reena froze in fear. 

"The voice..." Reena felt despair as the hall's entire psychic shield wavered. The Sea of Quanta, the location of the Archon Hall, was protected by state-of-the-art technology that protected it from the sea itself. Only one creature lived in the depths of the sea, she did not know what it was but her father, the Anemo archon/Herrscher hybrid made contact with it. 

The Archon Hall was created not just as a home for the other versions of her father but as a way to contain the beast. The beast in the depths of the sea and the creature beloved by the Sea of Quanta. 

"The song is still... to think it's just asleep..." Reena whispered as she drew into the reserves of her own gnosis to fight back the psychic attacks. 

"I need help..." 

0-0-0-0-0

"Ah! Mei's fresh panties!" 

"Kiana-chan!" 

"Allowing anti-Kiana protocols, Kiana Idiotka must not molest Mei-Onee-sama. 

The herrschers of Truth, Origin, and Finality blinked as a portal opened under them. 

"Kya! Mei-senpai!" 

"Kiana-chan!" 

"everyone!" Seele Vollerei said with a smile as the Herrscher of Rebirth landed and lowered them to the ground. 

"Ehe!" 

"Hm... interesting," 

A young woman with purple hair dressed in a purple kimono eating some Dango and reading a book landed on the ground with a kotatsu. 

Nearby, a child wearing a white and green dress landed on the ground gracefully while a young lady with white hair and blue streaks shivered and held her head. "Are you alright?" Neuvilette asked only for him to hold his chest as he felt it. 

Numerous other people appeared in the theater. 

A young child around 5-8 landed on the ground of the theater. Her pink hair flowed as if she was underwater and she wore some cute clothes. She was covered in some sort of purple aura with hints of green. 

"Wheee!!!" The child cheered as she hopped off the platform and floated as if she was underwater. "This is amazing!" 

"Reese! Get down from there!" Kiana shouted as she looked at the floating child. 

"Bleeh! Come catch me, auntie!" Reese teased as she swam around while a young woman with dark hair tied into a ponytail looking a lot like Fu Hua, dressed in a beautiful set of clothes, appeared in front of them. "Ena!" 

"Hello, Reese," Reena greeted with a smile, effortlessly catching the floating child in her arms. "Greetings, everyone. I apologize for taking all of you here, but I need your assistance with—," 

The entire pocket dimension pulsed and shook, cutting the young woman off. 

"You okay?" Wanderer asked Nahida who trembled a bit. 

"I'm fine," Nahida said with a smile as she held her head. 

"It's this strong?!" Reese whispered as she looked at the people currently in the hall, a lot of them were affected and many of those were already damaged a lot. 

"This one..." Cloud Retainer, the human version, whispered while fixing her glasses. "Ganyu, Shenhe, stay strong," 

Ganyu nodded while gritting her teeth. The silent Shenhe nodded with sweat dripping off her body. 

The knights of Favonius were on the same page except for Kaeya, Diluc, Jeanne, Albedo, and Lisa. Lisa's eyes widened as she drew a sigil and used her magic to create a barrier around them. 

"A mental attack?" Childe whispered while holding his head. The harbingers of the Fatui looked at each other. Pierro, the director of the Fatui Harbingers, paled and breathed heavily while his nose bled. Dottore noticed the people and those who were affected. Even the traveler became victim to the psychic wave while the child held in the woman's arms remained blissfully unaware. 

In that instant, Dottore fell to the ground, his mask shattered as blood poured from his nose, his hands turning to the effigies of tentacles. 

"! Dottore!" The jester called out to the doctor, watching in horror as the Doctor himself transfigured and transformed into something. The sages of Sumeru, on another part of the hall all did the same. 

"Quick! Flare your powers!" Reena shouted as she noticed the transformation. Her aura overpowered and blanketed the area while she held Reese close, making sure she couldn't see or hear as screams of horror and pain echoed in the hall. Kiana's eyes widened as she saw some humans transform into eldritch horrors. 

All those who heard her did the same. Dottore, whose body was halfway transformed, returned to normal but something was wrong. 

'His brain...' the jester thought. 'heavily damaged...' 

"What was that?!" Paimon shouted in fear as she hugged Lumine. 

"A psychic attack from the Beast of the depths," Reena said with a frown as she looked into the sea of quanta. 

"The beast of the depths?" Skirk asked, looking at Reese with wide eyes. "Are you sure it's that one?" Skirk asked, shivering slightly. 

"You know about it, master?" Childe asked the woman. 

"Yes... The all-devouring Narwhals... one of them managed to reach the beast of the depths. We did not know what happened but it died. It died so fast before it even reached a tenth of where the weakest influence of it." Skirk whispered as she remembered how she tried to capture the all-devouring Narwhal. For what seemed to be a single moment, the Narwhal froze and died, turning into a mass of corals and tentacles. 

"I'm sorry for the sudden event but one of the thrones was destroyed and I needed your help," Reena said with a bow. "Welcome to the Archon hall, or by its true name, the Theatre at the Edge of Time," Reena said with a smile.

"Hey! Reena! What about them?" Reese asked, looking at a group of people. A group that Mei knew. 

Dr. MEI and KEVIN hugged each other as tightly as they could while the rest looked at each other. "Their knowledge and expertise are needed as well," Reena said with a smile only for Miss Pink Elf, the prior incarnation of Reese's mother to lean in with a smile. 

"Oh my~ You look a bit like HUA! The both of you are!" Miss Pink Elf said with a smile, her pointy ears wiggling as she looked at Reese and Reena and then at HUA. 

"WAR! CHAOS! DESTRUCTION!" A masked man with white hair shouted. 

"WAR CRIME! BLOOD FOR THE BLOOD GOD! GENEVE SUGGESTION FOR THE INFIDELS!" Reese shouted with fervor and glee causing both Kalpas, Reena, and those who heard her to look at the child. 

"HAHAHA, YOU WILL BE MY APP—," A green tentacle pierced through the barrier of the theatre at the age of time, slamming the thin tentacle the size of a baseball bat on the head of the Flame Chaser. The entire theatre shook as a large crater and Kalpas was embedded several tens or hundreds of meters deep into the Theatre's dimension. 

"Wah!" Instead of fear, Reese hopped off the arms of the hostess of the theatre and embraced the tentacle. "HEY! TAKOTAKO! IT'S ME!" Reese gleefully embraced the tentacle with no hint of fear. 

In an instant, the tentacle disappeared, only to be replaced by a green slime. "YAY! TAKOTAKO IS HERE!" Reese said with a bright smile while Kalpas, covered in magma or something, crawled out of the crater. 

Rex Lapis, or by his name, Zhongli, looked at the slime. Memories of the Archon war pulsed back to his brain. That thing... held more destructive potential than Osial or Celestia ever had... only held back by the whims of a child. 

"Please don't be too loud. Outside of certain areas, the beast of the depths can hear us.... it is still asleep as of now," Reena said with a sigh as she used her powers to create and patch the barrier up. "Food and refreshments have already been prepared, entertainment as well." 

"FIGHT ME!" Kalpas shouted and before anyone could stop him, he fell to the ground convulsing as Reena withdrew the barrier protecting them where he stood in annoyance. "He'll be fine. We are on the edge of The Beast's influence. It's the weakest here," 

"Want some wine?" Venti asked as he showed a bottle of wine into a bottomless abyss. Zhongli looked at his old friend with a raised brow before remembering some things. He approached the bard and kicked him into the Abyss. 'He'll be fine,' Zhongli thought as he followed Hu Tao inside. he felt the flow of energy in this realm and it was highly stable. Fragments of his and Barbatos' powers flowed as well and it seems like the psychic attacks were not intentional. 'The beast of the depths... even in its sleep, it can destroy Teyvat if it neared our world,' Zhongli thought. 

Deeper, ever so deeper. To the depths and to the end. I exist

What am I?