Another day, another bizarre encounter.

Ash was starting to think that every Servant in Chaldea had some kind of strange quirk. Whether it was Musashi's endless love of food, Jeanne Alter's aggressive attitude, or Gilgamesh's insufferable pranks, each Servant was their own brand of chaos.

And today… well, today was no different.

As Ash and Pikachu made their way through Chaldea's halls, looking for Da Vinci's lab, a sudden purple flash appeared before them.

"Ta-da~! BB-chan has arrived!"

Ash blinked in confusion as a new figure materialized right in front of him.

A mischievous-looking girl with long lavender hair, bright purple eyes, and an eerie yet playful smile stood before them. She wore an almost futuristic black-and-purple outfit that screamed "troublemaker," and something about the way she looked at Ash sent shivers down his spine.

Ash took a cautious step back. "Uh… who are you?"

The girl giggled and placed a hand on her hip. "Ara~? You mean you haven't heard of BB-chan? Oh my, how tragic! To be forgotten before even being introduced! Senpai, you wound me~."

Ash blinked. "...Senpai?"

Pikachu tilted its head. "Pika?"

BB clasped her hands together and sighed dramatically. "Yes, yes, you adorable little rookie Master, from today onward, I shall refer to you as Little Senpai!"

Ash frowned. "Little Senpai?"

BB's grin widened. "Little Senpai!"

Pikachu snickered. "Pika pika~."

Ash scratched his head. "Uh… yeah, I don't get it. Why are you calling me that?"

BB pouted and waved a finger at him. "Ah-ah! Silly Little Senpai, there's no need for you to understand BB-chan's logic. Just accept it and let BB-chan pamper you~."

Ash raised an eyebrow. "Okay… but why do you keep calling yourself BB-chan? Why do you talk in the third person?"

BB froze.

A sudden shadow fell over her face, her playful aura darkening just a bit.

Then—POOF!

She suddenly materialized right behind Ash, wrapping an arm around his shoulder while whispering in his ear. "Little Senpai~... are you saying BB-chan's way of speaking is weird?"

Ash stiffened. "Uh—"

BB tightened her grip. "Are you saying BB-chan's adorable charm isn't to your liking?"

Ash gulped. "That's not what I—"

BB suddenly pulled away and dramatically placed a hand over her forehead. "Oh, the agony! The heartbreak! BB-chan is being rejected by her own Little Senpai! How could you be so cruel?!"

Ash groaned. "Oh come on, really?!"

Pikachu giggled. "Pika pika~!"

BB pouted, crossing her arms. "Hmph! BB-chan was going to be nice and take you on a little tour of Chaldea, but if you're going to be such a spoilsport…"

Ash rubbed the back of his head, exasperated. "Look, I didn't mean to offend you or anything, it's just—"

BB suddenly leaned in very close, her golden eyes glinting with mischief. "Oh~? So Little Senpai does care about BB-chan's feelings?"

Ash immediately took a step back. "Hey! Personal space!"

BB laughed. "Hah! Oh, you're just too much fun to tease, Little Senpai~!"

Ash sighed. "Great… another troublemaker."

BB winked. "Oh, don't worry! BB-chan is nothing like that golden jerk Gilgamesh. I promise I only tease you because you're adorable~."

Ash's face twitched.

Pikachu, now fully entertained, watched as Ash mentally prepared himself for yet another chaotic Servant to deal with.

One thing was clear—BB-chan was going to be an absolute menace.

Later that day, Ash and Pikachu were training with Mashu in one of Chaldea's simulation rooms.

Mashu was patiently explaining how to properly direct Servants in battle. She demonstrated footwork, positioning, and how Masters should conserve magical energy to keep their Servants strong in combat. Ash, being used to Pokémon battles, was picking things up quickly, though he still struggled to get the hang of using his Command Seals properly.

"Senpai, you're doing great," Mashu praised with a soft smile. "With more practice, I think you'll—"

"Found you, Little Senpai~!"

Ash froze at the sound of that all-too-familiar sing-song voice.

"Oh no…" he groaned, already knowing what was coming.

POOF!

With a flash of purple light, BB appeared out of nowhere, striking a dramatic pose.

Pikachu let out a small snicker. "Pika pika~."

Mashu blinked in surprise. "BB-san?"

BB twirled on her heel, hands on her hips, and grinned devilishly at Ash. "My, my~! Look at you, so serious, so hardworking! How unlike my cute little Senpai! Are you sure this is the best way to spend your time? BB-chan thinks it would be sooo much more fun if we played instead~."

Ash sighed, rubbing his temple. "BB, we're training."

BB waved a dismissive hand. "Pffft, training, schmeaning! Why struggle when you have BB-chan? If you need something, I can totally hack the system and give you unlimited Command Seals! Or better yet—I can just 'delete' your enemies and call it a day~."

Mashu's eyes widened. "W-Wait, BB-san! That would be unfair!"

BB winked. "And?"

Ash frowned. "Yeah, I don't think cheating is really my thing."

BB gasped, placing a hand over her heart dramatically. "Little Senpai! Are you rejecting BB-chan's generosity? How could you! I'm just trying to make your life easier!"

Ash crossed his arms. "If I can't win a battle fairly, then it doesn't count. That's not how I do things."

BB pouted in exaggerated disappointment. "Ugh, you're such a goody-two-shoes, Little Senpai."

Mashu, smiling slightly, nodded in approval. "That's just who Senpai is."

BB gave Ash a pointed look before sighing dramatically. "Fiiine, fine. If my Little Senpai insists on being boring, I guess I'll just have to entertain myself another way~."

Ash immediately stiffened. "Wait, what do you—"

POOF!

BB teleported right behind him, wrapping her arms around his shoulders. "What if I gave you special BB training~? You know, the kind that only BB-chan can provide~."

Ash jumped away like he'd been burned. "Nope! Nope! No way!"

BB giggled. "Oh come on, don't be shy~."

Pikachu was rolling on the floor laughing. "Pika pika pika~!"

Mashu, meanwhile, stepped in between them, looking a bit flustered but maintaining her usual politeness. "BB-san, please don't tease Senpai too much."

BB gave an exaggerated sigh. "Ugh, fiiine. But only because Mashu-mashu asked so nicely."

Ash exhaled in relief. "Thank you, Mash."

BB smirked as she suddenly materialized a floating holographic screen beside her. "In that case… how about I just monitor your training? I can record all of Senpai's cute moments and save them for later~."

Ash turned pale. "You can what?!"

BB giggled. "Relax, relax! BB-chan wouldn't do anything bad with the footage… probably~."