Continuing with chapter 1 (part 1):

The next morning at 7am, Ciel still couldn't get out of bed because now baby Rimuru was hugging Ciel and wouldn't let her go. 

Later she said

Ciel: Rimuru sama, can you let me go, so I can cook breakfast for you.

 Rimuru heard Ciel's voice, he didn't say anything but his hand released on its own and rolled over and continued to sleep. 

Ciel looked at Rimuru and thought "master is so cute, while master is sleeping".

After saying that, she went to the kitchen to cook, and after cooking, she was about to tell Rimuru to come down to eat but saw Rimuru there and Diablo next to him.

Diablo: Ciel sama, can I feed Rimuru sama to eat .

Ciel thought for a moment and allowed Diablo to feed Rimuru to eat, because she still had to deal with Rimuru's paperwork, because Rimuru was in a baby form, so she has to worked for Rimuru one day. Diablo then scooped up a spoon to cast for Rimuru to eat.

Rimuru: What is this?

Diablo: this is the dish that Ciel sama cooked for you.

Rimuru tasted a spoonful and said:'hmm Delicious

(Author: imagine Rimuru in this image as a baby.)

BONUS

(Author: Not very relevant, but imagine if Shion heard that Diablo feed Rimuru to eat.)

(Author: Ok let's get back to the story.)

After finish eating, Rimuru wanted to find mama (Ciel) to play with. Right now Ciel was having a headache and was tired of doing Rimuru's papers.

Ciel: SO BORING.

Then she heard a knock at the door.

Ciel: come in.

When the door opened, someone ran in and hugged her. Yes, it was baby Rimuru.

Rimuru: mama, I wanna play with you.

Ciel: Sorry, I'm busy right now so I can't play with you, why don't you play with Diablo.

Rimuru: I just want to play with mama.

Diablo was a bit sad to hear that.

Ciel: you can leave now Diablo.

Diablo: Yes, Ciel sama.

After Diablo left, Rimuru was currently sitting on Ciel's lap, since she said before that she would play with Rimuru when she was done, so Rimuru sat on Ciel's lap to wait for Ciel to finish her work.

Ciel(thought): this is so embarrassing, master is sitting on my lap.

 Ciel also blushed slightly as Rimuru sat on her lap, then she turned back to do Rimuru's paperworks. While working, there was a "boom" sound, the door flew open and the person standing in front of the door was Veldora.

Veldora: Hey Rimuru, I finished this manga, do you have another manga for me to read?

But the person he saw in front of him was Ciel, on her lap was a child about 2 or 3 years old, with the face same as Rimuru with blue hair and yellow eyes, Veldora asked after seeing that.

Veldora: Ciel, who is that baby, don't tell me it's yours...

Rimuru: mama, who is that person?

Ciel was about to tell Rimuru who is the person in front of Rimuru and at the same time wanted to explain to Veldora that this child was Rimuru, but then Veldora shouted.

Veldora: what, my best friend got married and didn't invite me to the wedding, he even did that to Ciel and had a baby!!!!!?

Hearing Veldora scream, Rimuru immediately cried and Ciel looked at Veldora with scary eyes. Seeing that, Veldora fell scared and apologized to Ciel because of his loud voice. Ciel then explains everything and says that this baby is Rimuru. Veldora froze for about 2 minutes.

Veldora: So this child is Rimuru right?

Ciel: That's right, it's only 7 hours left before he returns to his original form.

Veldora immediately picks up Rimuru, smiles, then says: so cute, I never seen my best friend as cute as this, hope the FBI doesn't come here to arrest me.

Ciel: You read too much manga, Veldora.

When Rimuru saw Veldora smiling, he smiled along and said: onne san.

Veldora was frozen for another 2 minutes, Ciel couldn't hold her laugh, after 2 minutes Rimuru asked: Are you OK, onne san.

Veldora at this moment wanted to shout at Rimuru, but since Rimuru was in a baby form and didn't know much, so Veldora taught Rimuru what is onne san and what is onni san. When he finishing teaching, Rimuru says: can onni san play with me.

Veldora by all his experience of reading manga, he knows how to handle this situation, he played with baby Rimuru by throwing Rimuru up, causing Rimuru to almost touch the roof and then catch Rimuru back . When Veldora was playing with Rimuru, there was a "boom" sound at the door.

Veldora: Oh no, the FBI is here to arrest me right?

But the person standing at the door was not the FBI, but it was Milim.

Milim: Uncle Veldora, how dare you call me, this demon lord is the FBI.

Veldora: What are you doing here?

Milim: Of course, playing with my bestie, Rimuru.

Milim looked at the person at the desk, it was not Rimuru, but Ciel, Milim asked: hey Ciel, where is Rimuru?

Ciel: Veldora is holding him.

Milim looked at the baby, who was being hold by Veldora, and realized that the person had the same face as Rimuru, later she realized that person was Rimuru.

Milim: is this Rimuru, why was he turned into a baby?

Ciel then explained why Rimuru was turned into a baby. After listening to Ciel's explanation, Milim understood everything and told Veldora.

Milim: Uncle Veldora, give me Rimuru, so I can play with him.

Veldora: no, I'm the one who will play with Rimuru.

After that, the two of them fought, Ciel didn't care much, she continued to do Rimuru's paperwork because she said before that: if Rimuru cries or something, she will not forgive the two of them. 

After working for a while, by the time Ciel finished the paperwork for Rimuru, it was already afternoon. At this time, Shuna knocks on the door and tells Ciel sama and everyone to come down for lunch. Of course, during lunch, everyone fought to feed Rimuru. After lunch, it was now 1 hour before Rimuru returned to normal. Everyone is currently playing with Rimuru, while Veldora meets Ciel to ask her about the next manga.

Veldora: I know you have the ability to see Rimuru's memories, can you give me the new manga

.Ciel: I did look at his memories, but I didn't watch those manga things...Saying this, Ciel immediately blushed. Veldora saw that and thought about things that would make Ciel blush. Later he realizes what can make Ciel blush, are those love or something called XXXX things???! Veldora thought so, he left immediately. After 1 hour, Rimuru returned to normal.

Rimuru: What's happening here, why are all you guys here?

Shuna: you were turned into a baby and we took care of you.

Shion: yes, you are very cute.

Rimuru: why did I turn into a baby? 

Benimaru and Zegion explain to him why he was turned into a baby.

Veldora: Hey Rimuru, I haven't dealt with you yet about you calling me onne san.

Rimuru: nani, I call you onne san?!

To avoid Veldora from handling him, he immediately gave Veldora some manga. After a while it was already night, Rimuru returned home after a long tiring time with everyone, even though he didn't know what tired was. When he opened the bedroom door, he saw Ciel sitting on the bed.

Rimuru: Ciel, what are you doing here?

Ciel: you don't call me by that word anymore.

Rimuru: what, what word did I call me?

Ciel blushes and says you called me............ma...ma.

Rimuru (thinking): Nani, did I call Ciel mama?! He thought as he blushed.

Ciel: you even asked me to sleep with you, while sleeping, you even touched my breasts, even squeezed, but I like that. Ciel said as he let out a lewd smile.

Rimuru: what the ****, what did I do to Ciel.

Ciel: so from now on, I will sleep with you, if you do something like that to me, please do it a little stronger, my dear master❤️.

End of chapter 1.