What happens when you summon Emiya Shirou in Chaldea

Baby Shirou

Fujimaru Ritsuka has seen many things in his entire life, and that is saying something considering that he somehow got whisked away from his normal life into a world where unexplainable things happen daily, spirits of heroes manifested in real life, dealing with singularities that are based off from branches from the main timeline of his universe, and many others.

All and all, because of the events he has endured during his time as a master of Chaldea, he has gained a lot of experience and knows how to deal with various situations.

But the situation he was currently in right now...he has no experience on how to deal with it.

And that situation...was him, holding a baby in his hands. The funny thing is though is that the baby is Shirou himself.

Ritsuka let out a sigh as he looked at Shirou, who was sleeping. "Just how did things end up like this...?" Ritsuka thought as his mind went back to an earlier time period...

(Earlier...)

Ritsuka was walking towards Da Vinci's room, planning to ask her something. "Hey Da Vinci! Are you in here? I need to ask you about something!" Ritsuka said.

"Hm? Ah, well come in..." Da Vinci moaned in response.

Ritsuka was worried upon hearing Da Vinci's tone of voice. "Are you okay Da Vinci? You sound a bit tired."

"Y-Yeah! Just come in, although you're not going to believe what you're about to see..."

Ritsuka was even more confused. "What does she mean by that? I guess Da Vinci probably made something that shouldn't exist...again..."

Wanting to see what was going on over there, Ritsuka entered Da Vinci's room to see what was going on in there. As he did, his mouth dropped upon the sight in front of him.

In front of him was Da Vinci, who looked exhausted and was holding a baby with familiar red hair that was bundled in Shirou's white kimono. And upon seeing the red hair and the white kimono, Ritsuka immediately knew who the baby is.

"Um...Da Vinci...is that-?"

"Yes. The baby you're seeing in my hands right now is Shirou," Da Vinci replied with a sigh.

For a moment, Ritsuka didn't say anything as he was trying to process the information Da Vinci just gave him. After a few seconds of silence, Ritsuka then began to continue the conversation. "Okay. Explain what happened to him."

Da Vinci let out a chuckle. "Well...it's a long story. Earlier, Shirou came by to drop something off for me, and I asked him to put it on top of the bookshelf over there," she said as she pointed at a huge bookshelf in a corner of her workshop. "However, that's when the trouble started."

Ritsuka let out a small sigh. "What happened?"

"One of the items that was included in the box fell onto Shirou when he was trying to put it on the bookshelf, and that item...well..."

"Well, what, Da Vinci?"

"...That item was the same youth potion from a while ago, but a lot more potent than before."

Ritsuka mentally groaned at the news Da Vinci just gave him. "Really Da Vinci? You happened to have a more effective version of that youth potion lying around in that box? Jeez, I don't know what's scarier; the singularities I had to face, or what shenanigans Da Vinci is thinking of..."

"Ritsuka? Are you there Ritsuka?" Da Vinci hollered, snapping Ritsuka out of his thoughts.

"Hm? Ah, yeah. So...Shirou's been turned into a baby huh?"