In all of the realms, he alone is... [Honkai Impact 3 x Pokemon Fanfiction]

The voice in the depths

Back in St. Freya academy, a bright flash erupted in one of the academy's signature teleport rooms, revealing a wet-haired Rex with a grin on his face while his older brother, Reve, patted the body of his partner, Metagross.

 "So, your quota for the week is done?" 

"Yep! I already finished my ground-type specialization certificate," 

"Good, you know, you can go to the advanced courses, right? Your ground-type team is terrifying," Reve said with a shiver as he remembered how a pair of dragon-ground Pokemon on Rex's team demolished a competition a while back. To think Rex's starter was around the same level as... well, considering how his and Rein's starters were... 

"I already have an advanced license for a Pokemon type," Rex said with a smile while his Swampert nodded. "I only wanted a license for ground types for my next ruins exploration," Rex said with a smile. 

"You brats, where have you been?!" A familiar voice belonging to a young woman that was a part of their nuclear family.

Bountiful red hair bounced with each step as Professor Himeko approached them, followed by her partner, a Delphox/ 

"I was surfing on the storm beach," Rex replied with a cheeky smirk. "Rein was flirting with some sexy ladies on the beach," Reve turned to his younger brother with wide eyes only for the both of them to yelp in pain as Himeko reached and pinched their ears.

"Big sis!" 

"This is Child abuse! Get this old hag off me!" 

"An old hag, huh? I helped change your diapers, you brat!" Himeko roared while grinding her knuckles on Rex's head while Reve. 

"Say, Rita," The younger brother immediately approached the psychic-type specialist to.

"Sorry, Reve. But I have things to do." 

"HAH! YOU EVEN INHERITED THIS OLD HAG— NO STOP!" in the background, Rex can be seen getting Boston Crab-ed by Professor Himeko. 

"Yeah... those two are my brother and surrogate sister," Reinhardt said as he stood with Elysia on the second floor of the teleport room. Elysia giggled sweetly as she spotted the two before turning to Reinhardt. 

"You all have the same hair color," She whispered. 

"Yup!" 

"GET A DATE FIRST! OW! OW! STOP! DON'T FUCKING JOIN IN, REVE!" 

0-0-0

Dressed in regular clothes, Rex winced as he sat on the chair in front of Himeko's desk. 

"Are you sure about this, Rex?" Himeko asked. Gone was the annoyed young woman, replaced by the caring older sister who helped raise him. "You know you already have the license and certificate for ground-type Specialization. If you get the advanced license then you can work in Gyms and other facilities as a ground-type trainer," 

"I know, but I already have an advanced license and certificate like Rein and Reve," Rex said, looking at the symbol on his trainer ID. The primary affinity that he and his brothers along with his entire family shared. 

"I know, but Rex..." 

"I'm searching for the sea temple, the one known as Atlantis," Rex said with a smile, remembering how he first saw that place. 

Rex, with a rebreather in his mouth, held onto his Swampert as the underwater currents surged and increased. His grip loosened a bit and when he was about to slip, a Wailord managed to push him into a place, Atlantis, an underwater temple created from an unknown dimension that now drifts on the underwater currents.