What happens when you summon Emiya Shirou in Chaldea

Splitting Shirou and Sengo

Pseudo-servants are Servants that have manifested utilizing humans as their vessels. While like Demi-Servants in the result, the process of forming one is different. Pseudo-Servants are the result of Heroic Spirits and Divine Spirits that cannot become Servants due to an inability to take a physical form, so they are instead summoned by using a compatible human body to act as a vessel. The resulting Servant cannot be called either individual, but a combination of the powers of both individuals mingling together that add abilities do not present in the original Servant. The thoughts and personality may fully conform to that of the human vessel as well should the spirit decide that it is best to give over control or if the human vessel's will overpower the spirit's, or it may manifest as a combination of their respective personalities. However, if the possessing spirit is a Divine Spirit, the human vessel's memories and past will be sealed to protect the vessel's mind regardless of how the personality manifests.

In Shirou's case, despite being the pseudo-servant vessel to Sengo Muramasa, he still retains his mind and actions and gained his noble phantasm. However, they can switch minds if they want to.

Normally, it would not be possible to split the heroic spirit from the vessel itself...

Until now that is...

Right now, it is lunch time in Chaldea's cafeteria. Normally, it meant that Shirou would be at the cafeteria catering to Arturia and her counterparts, Ishtar and her counterparts, Parvati, Kama, BB and her sisters, Illya and her counterparts, Miyu, Astraea, Irisviel, Jaguar-man, and Kiritsugu alongside with EMIYA and EMIYA Alter helping him.

However, today was different from their usual days.

Because Shirou was not here yet.

However, unlike before, everyone was not worried as they knew that Shirou was stuck doing something for Da Vinci.

"Hey, Shirou's not here yet," Arturia Alter said.

"Relax. He's just stuck doing something for Da Vinci again," Arturia said.

"Yeah. And when it comes to her, she's bound to ask him to do something crazy again, even if it's not an experiment," Arturia Lily said.

"Indeed. Remember the last time Shirou was late here?" Lancer Arturia asked.

"Oh yeah. That was the time he got turned into a girl, correct?" Lancer Arturia Alter said.

"Yes. To be fair, that time was Merlin's fault," Ruler Arturia said.

"Exactly. Then there was that time where Shirou got turned into a kid because of a youth potion made by Da Vinci herself," Archer Arturia said.

"Eh? That happened before?! Along with Shirou turning into a girl by Merlin?!" Caster Arturia said in shock.

"Yeah. And we had to watch over Shirou when he was turned into a kid for a while," Rider Arturia Alter said.

Santa Arturia Alter nodded in agreement. "And he was so cute, I'll admit..."

"Wow...just what did Shirou look like when he was a kid?" Caster Arturia asked.

Mysterious Heroine X let out a smile. "He was so adorable!" she said happily.

"Yeah. He was so adorable that when it was my turn to watch over him, I have him a few of my sweets I've been saving up," Mysterious Heroine X Alter said.

"And don't get me started on when he wore those bunny ears..." Mysterious Heroine XX said as she fondly remembered the time Shirou wore Ruler Arturia's fake bunny ears as a kid.

"Wow..." Caster Arturia said in amazement.

"Mou! Where is Emiya-Kun?!" Ishtar asked in annoyance.