This is how Thomlight's birth goes in The Birth of Thomlight Sparkle.
[We view Thomas speeding at full speed towards Golden Oaks Library, with Annie and Clarabelle]
Thomas: Cinders and Ashes! I can't believe this is happening!
Annie: Slow down, Thomas! What's with all the excitement?
Thomas: Just a few days ago, I received word from Princess Celestia that Twilight and I were going to have a foal and guess what, she was right!
Clarabelle: I know! But you don't have to get all excited about it.
Thomas: Just wait until we get there.
[They arrive at Golden Oaks Library. Thomas chuffs over to Twilight, who is feeling an awful pain]
Thomas: Twilight, it's time to go to the hospital.
Twilight: Okay, Thomas. Just a minute.
[she slowly gets up as Nyx stays by her side]
Percy: Thomas, what's up with Twilight? And why is she groaning in pain?
Fluttershy: [gasps] Is she... dying?!
Thomas: No, Flutters. Twilight is not dying. She's giving birth to our first foal that's all.
Pinkie Pie: [perks up] REALLY?! [screams with excitement] I didn't know you two were having a foal! [bounces around the room with excitement]
Applejack: Ah' can't wait to see him!
Rainbow Dash: I hope he's awesome.
Henry: Get well soon, Twilight.
Twilight: Don't worry about me, Henry. I'll be fine once I give birth to our foal. [boards Annie with Nyx]
Nyx: I can't believe it! I'm going to be a big sister soon.
Thomas: Yes, Nyx. You are. [whistles and drives away]
[later, at the hospital,]
Shining Armor: Wow! I can't believe my little sister is having a foal like us. I'm sure he'll make good friends with Skyla.
Cadance: Yes, Shining. I'm sure he will.
Skyla: I can't believe that you're getting a brother, Nyx. I could learn so much from him.
Nyx: Yes, Skyla. You could.
Skyla: I wonder what he'll look like?
Nyx: Well, he's said to have half my mother's features and half my father's features.
Skyla: Sounds good.
Thomas: I know, Skyla. [sighs] I hope Twilight's okay.
Nurse Redheart: Thomas, It's time.
[They enter Twilight's room and Thomas notices the tiny foal in her hooves]
Thomas: Twi, he looks great.
Twilight: I know, Thom. I know.
Skyla: He looks so cute.
Nyx: I know, right?
Rarity: He's adorible.
Twilight: What do you guys think we should name him?
Fluttershy: Well, since he looks half like you and half like Thomas, I think you should name him "Thomlight Sparkle."
Thomas: Thomlight Sparkle. I love that name.
Twilight: I do too. It fits him perfectly.
Skyla: Hi, Thomlight. My name is Skyla.
Thomlight Sparkle: Skyla.
Thomas: His first word.
Twilight: I'm so proud of you.
[a few years later]
[we view Thomlight, now a teenage colt, and Twilight walking side by side and heading for Nyx's room]
Thomlight: I can't believe I actually have a sister! What does she look like, Mom?
Twilight: You'll find out once we get there.
[They reach Nyx's room and Twilight opens the door]
Twilight: Here she is.
Thomlight: Hey, so, you must be my sister, Nyx.
Nyx: [turns to him] Yep. That's me.
Thomlight: [notices the slits in Nyx's eyes] Mom! She's Nightmare Moon! Go! You run whilst I hold her off!
Twilight: No, Thomlight! She's not Nightmare! She looks like Nightmare Moon only her mane and tail are different.
Thomlight: Oh. Sorry, for mistaking you for a villain.
Nyx: That's okay.
Twilight: Thomlight, Nyx was orphaned a long time ago and then Skyla, Snowdrop, and Yuna found her and then me and your father adopted her.
Thomlight: Wow! I didn't know you had that much history.
Nyx: Neither did I!
Twilight: Why don't you two tell each other about yourselves. I'm going to go and visit Zecora so I'll put your father in charge.
Thomlight: Okay, Mom.
Nyx: Have fun at Zecora's!
Twilight: Okay! [leaves]
Nyx: So, what has mom been teaching you?
Thomlight: She told about these weird train-like Transformers knowns as the Trainbots and the Deceptitrains. What's your life been like?
Nyx: Well, I have encountered many villains such as Tirek, Diesel 10, Megatron, Starscream, Unicron, Nightmare Moon, Lockdown, and the Dazzlings.
Thomlight: The Dazzlings? Who are they?
Nyx: Sirens that were banished from Equestria a long time ago.
Thomlight: Okay. So tell me about this Maximal guardian of yours.
Nyx: His name's Cheetor. I met him a long time ago. And after a battle against a bad guy, Optimus Primal, leader of the Maximals, said that he could be my guardian and since then, Cheetor has protected me from all kinds of danger. I could ask Primal to give you a guardian too. I'll ask him about it tonight. That's a promise.
Thomlight: Really? You'd do that? Oh, you're the best sister ever. [hugs Nyx]
Nyx: Oh, sure. No problem. Anyways, do you want to meet the Maximals?
[He and Nyx leave the room and enter the Axalon]
Nyx: Cheetor, Rattrap, Primal, Dinobot, Rhinox, Silverbolt, Blackarachnia, Tigatron, Airazor, Depth Charge. There's someone I want you to meet.
[The Maximals come out and Optimus Primal steps forward]
Optimus Primal: Why hello there, Nyx. Haven't seen you in a while. How've you been?
Nyx: Great actually, Primal. Thank you. This is my brother, Thomlight Sparkle.
Optimus Primal: Greetings, Thomlight. I'm Optimus Primal, leader of the Maximals. And this is Cheetor, Rhinox, Rattrap, Dinobot, Tigatron, Airazor, Blackarachnia, Silverbolt and Depth Charge. I presume that Nyx has told you about us.
Nyx: Hey, Cheetor!
Cheetor: Hey, squirt! Where've you been hiding yourself?
Nyx: Well, I've been well. And I just want you to meet my brother, Thomlight Sparkle.
Cheetor: So, you're the new kid?
Cheetor: Nyx has been telling me about you.
Thomlight: It's nice to finally meet you in person.
Optimus Primal: Er, Cheetor, shouldn't you be telling him about the Predacons?
Cheetor: Okay. The Preds are like these dragon-like transformers. One of them who we know now was named Predaking and the other two were Skylynx and Darksteel. All three were created by Shockwave.
Thomlight: Oh. Those guys sound scary.
Optimus Primal: Oh, they are. One day, when they meet you, you'll find out how scary they can be.
Thomlight: I wouldn't like to come face-to-face with a Predacon.
Cheetor: Well, you won't have to, because there aren't any around at the moment.
Thomlight: Phew. That's good.
Nyx: Yeah. The Predacons were thrown into the Well of AllSparks during the Terrorcon battle.
Thomlight: Oh. So, how long have you and Nyx known each other, Cheetor?
Cheetor: For, well, you know, ages.
Nyx: What he means to say is, we've known each other for a long time.
Thomlight: Oh. So tell me about yourself, Primal.
Optimus Primal: Well, since I arrived here on Earth, I been protecting people on this planet in the name of my ancestor, Optimus Prime.
Thomlight: You have an ancestor? I didn't know that! Nyx, these guys are really cool.
Dinobot: So, you're the new foal in town?
Thomlight: Yeah. I am actually. Why'd you ask?
Dinobot: Because, I too, was a Predacon once. Until I betrayed my master and became a Maximal.
Thomlight: Oh. So, you guys and the Preds are like the Autobots and Decepticons.
Dinobot: That's right.
Thomlight: Wow! You guys have very much in common.
Nyx: Of course they do.
Twilight: Nyx, Thomlight! I'm home!
Optimus Primal: Uh-oh, you two better get outta here before your mom catches you. We can talk another time.
Thomlight: Okay. It was nice meeting you guys. See you next time. [leaves]
Nyx: Bye, guys! Bye, Cheetor!
Cheetor: See ya, Nyx! Bye, Thomlight!
[they leave the Axalon]
[back in Twilight's library]
Thomlight: Hi, Mom.
Nyx: How was your day at Zecora's?
Twilight: Pretty much went well. Yours?
Nyx: Went pretty good, actually. We learned so much about each other. I even introduced him to the Maximals.
Twilight: Wow! That's great! Anyways, it's time for bed. You should get tucked in.
Thomlight: Okay. [climbs into bed]
Nyx: Good night, Mom. [kisses Twilight and climbs into bed]
Twilight: Good night, you two. [leaves, turns off the light and closes the door]
Thomlight: So, I guess I haven't meet Optimus Prime yet.
Nyx: I'll introduce you to him in the morning. [falls asleep]
Thomlight: Okay. Good night, Nyx. [falls asleep]
Nyx: Good night.
[they both fall asleep]
[the next morning, Nyx takes Thomlight to meet Optimus Prime and the Autobots]
Thomlight: So, what are these guys like?
Nyx: Well, they have vehicle modes instead of animals.
Thomlight: And Snowdrop told me that one of them is named, Bumblebee.
Nyx: Yeah. She can sometimes tell people things she isn't supposed to. Anyways, here we are. [speaks into a microphone] Hey, there, Teletrann 1, it's me, Nyx.
Teletrann 1: Nyx? Oh, I remember you. I see have you have your new brother with you. What is your name, little one?
Thomlight: My name is Thomlight Sparkle.
Teletrann 1: Nice to meet you, Thomlight. What an honor. Please do come in. [the door opens]
[they head inside]
Thomlight: Nyx, this room is empty.
Nyx: You have to call out their names, that's the easy. Optimus, Bumblebee! Ratchet! Wheeljack! Bulkhead! Arcee! Ultra Magnus! Knock Out! Breakdown! Cliffjumper! I would like you meet my brother, Thomlight Sparkle!
Thomlight: It's good to meet you all.
Bumblebee: So, you're the son of Thomas and Twilight Sparkle!
Arcee: It's so good to meet you!
Ratchet: Any time you're injured, just come talk to me.
Breakdown: Nice to meet ya!