George & Harold in The Loud House: The Turtle Team-Up!

'George & Harold in The Loud House: The Turtle Team-Up! 'is an ongoing crossover fanfiction between The Loud House, Teenage Mutant Ninja Turtles, and Captain Underpants (although the only characters from that series are George & Harold), with a few elements from the Ben 10 series (original AND reboot, courtesy of DeviantART writer/artist KivaHoloTitan). The story started on November 14, 2017, and is still ongoing. The first arc, Louds in Space, follows Season 4's "Turtles in Space" storyline, with a few exceptions. It is a follow-up to fanfiction writer Scrappy-Doo-Fan's previous story, George & Harold in The Loud House: Season 1, Part 1 (currently cancelled).

As of January 30, the story currently adapts most of SDF's favorite episodes from Seasons 4 & 5, along with some original episodes inspired by previous TMNT incarnations.

Summary
Season 4, Pt. 1: George, Harold, the Loud siblings, and Clyde find themselves caught up in a race-against-time to reassemble a doomsday device & save Earth from destruction. But luckily, they've got the TMNT and their friends on their side! BOOYAKASHA!

Season 4, Pt. 2: Team Loud is back on Earth, and they're officially starting their ninja training! George, Harold, and Lincoln couldn't be more excited, but more weird things are happening in Manhattan, with our heroes caught in the middle!

The Loud Kids/Team Loud

 * Lincoln Jacob Loud (Daryl Sabara [present-day], Grant Palmer & Colin Dean [flashbacks]) - The 16-year-old middle child and only son of the Loud family, who has white hair and a chipped front tooth. Lincoln has a passion for comic books and is often shown reading them in his underwear. He often cosplays as the fictional superhero Ace Savvy. He breaks the fourth wall on a regular basis by speaking to the audience about the chaotic conditions and sibling relationships of his household. In "Louds in Space", he is shown to have a great love for not just comics, but pop culture in general, and is ecstatic upon going into space, as well as becoming a ninja-in-training under Leonardo's tutelage.
 * Clyde Zachary McBride (Bumper Robinson [present-day], Caleel Harris & Andre Robinson [flashbacks]) - A nerdy 16-year-old boy who is the best friend of Lincoln, George, & Harold and the adoptive son of Howard and Harold McBride. He is an African-American only child and spends almost all of his time with Lincoln. Clyde owns a walkie-talkie that he uses on missions. Clyde shares many interests with Lincoln such as video games and science fiction movies. He harbors an unrequited crush on Lori and tends to faint when she talks to him—though he finally conquered his nervousness when Lori finally started dating him. When Lincoln cosplays as Ace Savvy, Clyde dresses as his sidekick One-Eyed Jack.


 * Harold Munroe Hutchins-Loud (Keith Ferguson [present-day], Thomas Middleditch & Jason Ian Drucker [flashbacks]) - The 17-year-old schemer and second-adopted son of the Loud family, as well as Luan's boyfriend & the current wielder of the Omnitrix, who is commonly known for his green-striped T-shirt and blonde haircut. Since he and George were transferred to Royal Woods, they managed to become fast friends with Lincoln and actually managed to improve in school. He is shown to be a huge fan of the Teenage Mutant Ninja Turtles, and as of the [currently-upcoming] episode "City at War", he becomes Michelangelo's pupil and attracts the affection of Shinigami, much to Luan's irritance. He also inspires Mikey to abandon the 'Turflytle' persona (much to Raph's relief) in favor of the 'Turtle Titan' alter-ego. He is very enthusiastic when it comes to ninja training, and promises to complete any task as long as it means he gets closer to becoming a shinobi.


 * George Robert Beard-Loud (Kevin Michael Richardson [present-day], Veronica Taylor, Rachael Lillis, & Kevin Hart [flashbacks only]) - The 16 3/4-year-old voice of reason and 1st-adopted son of the Loud family, as well as the current wielder of the Nemetrix. During his time in Royal Woods, George became more of a ladies' man, and wouldn't hesitate to flirt with attractive females, which sometimes gets him into trouble. In "City at War", he becomes Raphael's pupil & begins to fall for Casey's adoptive sister, Angel (who was mentioned in "The Invasion: Part 2", but finally debuts in "City at War".)
 * Lori Dianne Loud (voiced by Catherine Taber & Jamie Marchi) – The 22-year-old eldest child of the Loud family and the only Loud child with a driver's license. Originally, Lori WAS dating Bobby, but before the events of the "Louds in Space" arc, she discovered that he was cheating on her, and started dating Clyde.
 * Leni Melissa Loud (voiced by Liliana Mumy [regular] & Eden Sher [understudy]) - The 21-year-old second-eldest child of the Loud family, as well as Raphael's girlfriend, who always wears sunglasses on top of her head. Leni is depicted as a beautiful, ditzy and air-headed dumb blonde who shows talents in fashion designing, wood-carving, and lock-picking.
 * Luna Harnell Loud (voiced by Nika Futterman) – The 20-year-old bisexual third-eldest child of the Loud family. Luna has a habit of speaking in a mock British accent. She is a wild and upbeat musician who owns various instruments, with her signature instrument being a purple Dean electric guitar. She very closely follows the words of her idol Mick Swagger and always encourages her family to "stay cool." Before the story arc started, it was stated that the other siblings had discovered that Luna was dating Sam, who was, in fact, female---but they didn't love her any less.
 * Luan Kravitz Loud (voiced by Monica Rial [regular], Kate Micucci [understudy], & Cristina Puccelli [flashbacks]) – The 19-year-old fourth-oldest of the Loud family and the comedian of the bunch who is Luna's roommate and Harold's girlfriend. Most of her dialogue consists of bad puns followed by her laughter and words "Get It?" much to the disdain of her siblings. She has braces, wears squirt-flowers on her shirt and shoes, owns a wooden ventriloquist dummy named Mr. Coconuts [whom she acknowledges as hers and Harold's "practice child"], and at some times will be seen with a camera. Every April Fools Day, Luan becomes a prank-obsessed maniac which leaves her family and Clyde in complete fear of the holiday as they try to avoid her pranks. In addition to being a comedian and occasional clown, there are instances where she is an expert mime artist.
 * Lynn Dwayne Loud, Jr. (voiced by Jessica DiCicco) – The 18-year-old fifth child and athlete of the Loud family. She tends to start competitions among her siblings and plays a large amount of sports like baseball, basketball, football, and soccer. In addition, Lynn can also be good at the various forms of martial arts like kickboxing, lucha libre, and parkour. She owns a soccer ball, a basketball, a football, and numerous hockey sticks. She is named after her father.
 * Lucy Edgar Loud (voiced by Debi Derryberry [present], Jessica DiCicco [flashbacks]) – The 13-year-old seventh child of the Loud family and Lynn's roommate. Lucy is a gothic girl with interests in poetry, séances, and gothic fiction as well as owning some pet bats. She has pale white skin and long black hair with bangs that conceals her eyes. Lucy also has an uncanny ability to suddenly appear in places, which often frightens her siblings. By the start of the story, she is still dating Rocky Spokes.
 * Lana Rodney Loud (voiced by Laura Bailey [present], Grey Griffin [flashbacks]) – The 11-year-old eighth child of the Loud family and the twin sister of Lola. Lana a fun-loving tomboy who loves to get her hands dirty, which often annoys Lola. She is also a skilled handyworker AND a plumber-in-training. Lana takes care of many animals that she keeps in her room where most of them are frogs and reptiles, so she gets along with the Turtles and their mutant allies.
 * Lola Loud (voiced by Grey Griffin) – The 11-year-old eighth child of the Loud family and the twin sister of Lana. Lola was originally a bratty girly-girl who was skilled at plotting and scheming to get her way, however, during the gap between the original story and the sequel, she's become a lot nicer.. Lola is mostly seen wearing a pink dress that conceals her legs and a tiara on her head. She is constantly entered in child beauty pageants and is the gossiper [formerly tattletale] of the group.
 * Lisa Marie Loud (voiced by Lara Jill Miller) – The 9-year-old ninth child of the Loud family and a child prodigy who has a PhD and is a Nobel Prize recipient. She enjoys solving complex equations and math problems and performing elaborate experiments where she would often using her siblings and Clyde as test subjects. She wears round glasses, speaks with a lateral lisp, and laughs maniacally when performing experiments. She sees Donnie as both a great lab partner...and a great source of genetic material for experimenting with.
 * Lily Loud (voiced by Kara Edwards) – The 6-year-old who is the youngest child of the Loud family and is mostly seen wearing a periwinkle-colored set of coveralls. Lincoln shares a special connection with Lily and babysits her on several occasions. Lily can walk independently and is occasionally carried by any of her older siblings or her parents for longer distances. Lily has been shown to be a fast learner as seen when she operates some technology.

The Ninja Turtles/Team Turtles

 * Leonardo (voiced by Seth Green until "The Return to Earth", where Benjamin Diskin takes over) – Leonardo, called "Leo" or "Leon" for short, is an enthusiastic ninjutsu student, who wears a blue mask, and fights with two swords called Niten Ryu. He leads the Turtles' missions.
 * Donatello (voiced by Rob Paulsen, later Charlie Schlatter) – Donatello, called "Donnie" for short, is in charge of the design and manufacture of all of the tools and weapons in the Turtles' arsenal. He is also a gifted hacker. He wears a purple mask and fights with a bō which also can be converted to a naginata via a blade inside one end of the staff. He originally had a crush on April, but he eventually came to terms with the fact that Mikey liked her more, and that it just wouldn't work out.
 * Raphael (voiced by Sean Astin, & later Scott D. Menville) – Raphael, also called "Raph", wears a red mask and fights with two sai. Known for his rage, he commonly takes it out on Mikey, but he tries to keep his cool whenever Leni is around, due to his massive crush on her.
 * Michelangelo (voiced by Jason T. Marsden, later Jaleel White) – Michelangelo, known as "Mikey", is the least mature of the turtles and is a lover of video games, skateboarding, pranks and pizza. He wears an orange mask and fights with two nunchaku which also can be converted into kusarigama via a blade inside of one of the sticks of each nunchaku and extra lengths of chain stored in the other. While he is very childlike, he can be quite mature and enigmatic, especially in a later original episode where he becomes Manhattan's newest superhero, the TURTLE TITAN! Not to mention, he has a gigantic crush on April.
 * April O'Neil (voiced by Grey Griffin, Mae Whitman [flashbacks]) – The sixteen-year-old daughter (17 since Season Three) of Dr. Kirby O'Neil and the love interest/crush of both Michelangelo and Casey Jones. Unlike her previous incarnations, she possesses extraordinary psionic/extrasensory abilities; having been born a human/Kraang mutant hybrid, as a byproduct of her late mother being experimented on by the Kraang before she was born, which she gradually learns to develop further and increase considerably in strength as the show progresses; particularly in Season 4 and Season 5. Her psionic aura varies from being transparent, to white, to yellow.
 * Casey Jones (voiced by Josh Peck) – The teenage son of a former NHL player at April's school who April is hired to tutor for an extra credit assignment. He later became an ally of the Turtles. He has a crush on April and a rivalry with Mikey because of it.
 * Professor Zayton Honeycutt / The Fugitoid (voiced by David Tennant [regular], Tom Kane [understudy]) – Zayton Honeycutt was an alien scientist from Dimension X. He originally created the Heart of Darkness as a power source until he was bribed by Kraang Subprime to sell it to them. Professor Honeycutt was reconstructed into an android after his body was destroyed by a Triceraton attack on his lab with his brain left intact. He replaces Splinter as the Turtle's mentor for the first half of the fourth season after he saved the Turtles, the Louds, April, and Casey with his ship the Ulixes.
 * Hamato Yoshi/Splinter (voiced by Hoon Lee) – Hamato Yoshi is the son and heir of Hamato Yūta, the leader of the Hamato Clan whose rivalry with the Foot Clan came to an end when he was a child. During a confrontation with the Kraang, Hamato Yoshi was mutated into a mutant rat upon coming into contact with a rat prior to the conflict. Since then ever since alluding the Kraang, he trained the Turtles in ninjutsu. During the Triceraton invasion, he is killed by Shredder but this attempt is foiled when the turtles travel back in time to save Earth. Following this, he takes on the Loud children as his newest pupils.
 * Hamato Miwa/Karai (voiced by Kelly Hu) – Hamato Miwa is the only child and willful daughter of Hamato Yoshi (Splinter) and the late Tang Shen, who was taken away from Splinter by Oroku Saki when she was just an infant and renamed Karai. Initially, she was their sworn enemy, but soon became a trusted ally after learning the truth about her parents and grew even closer to Leonardo. Karai later mutated into a violet-and-white snake where an extra chemical ingredient enabled her to shift back and forth and assume hybrid forms.
 * The Mighty Mutanimals – A team of mutant (& alien) animals that debut in "Battle for New York, Part 1." They were brought together by Jack J. Kurtzman to fight the Kraang.
 * Slash (voiced by Corey Feldman) – Originally named Spike, Slash is/was Raph's pet turtle. In the second season, Spike transformed into a mutant after jumping into spilled mutagen then renamed himself Slash in "Slash and Destroy". He is the leader of the Mutanimals.
 * Leatherhead (voiced by Peter Lurie) – An American alligator that was mutated by the Kraang after the parents of his owner flushed him down the toilet.
 * Pigeon Pete (voiced by A. J. Buckley) – A pigeon that was mutated by the Kraang and has a fondness for sourdough.
 * Jason / Mondo Gecko (voiced by Scott Innes [since "Earth's Last Stand"], & Robbie Rist [flashbacks only]) – Jason was a popular high-school skateboarder who while was skating was hit on the head by a canister of mutagen that was accidentally dropped from the sky by the Turtles. He mutated into a mutant leopard gecko due to his pet leopard gecko being on his shoulder at the time.
 * Dr. Tyler Rockwell/Monkey Brainz (vocal effects provided by Frank Welker in "Monkey Brains" & speaking voice provided by Tom Kenny since "Battle for New York, Part 1") – Dr. Tyler Rockwell is a neuroscientist who was mutated into a mutant-chimpanzee by Dr. Victor Falco. He eventually was again experimented on and gained the strong psionic abilities of telepathy and telekinesis; quite similar to April's. He emits a light purple psionic aura; whereas April's varies from white,to pale blue, to bright yellow.
 * Wingnut (voiced by Andy Berman) - An alien bat from the planet Huanu, who joined the Turtles in their quest to stop the Triceratons in order to avenge his fallen home planet.
 * Screwloose (voiced by Scott McNeil) - An alien mosquito from planet Huanu, and Wingnut's best friend. He puts on a courageous front, but is actually quite cowardly. Even so, he won't abandon his allies in the heat of battle—Heaven knows why...