Tengen Toppa Gurren Solvernia, by RandomNumbers523156, is, as shown by the title, a Gurren Lagann fanfic. It follows the basic main plot of the anime, while answering an unusual question: What if Nia were born in Jiha and Simon in Teppelin? From this question, a normal-haired, normal-eyed Nia is introduced, and shit goes down.The fic is currently ongoing, with 25 chapters released, and is just as maddeningly insane, if not more so, than its parent show.Tropes that take place in this fic:
Adaptation Expansion: Many minor characters have expanded roles and characterizations. Fairly notable is Kiyal, who upon her introduction forms a friendly rivalry with Nia that becomes friendship over time.
Also, characters from the Parallel Works appear too, like Cinoshisa, who is based on the masked commander of Parallel Works #6.
Action Girl: Yoko, of course. Nia slowly develops into one.
In addition, the First Prince is this to his younger half-siblings.
Birds of a Feather: Rossiu and Kinon are this, as shown prior to the big battle against Dai-Gankai; they share opinions and come to agreements, appearing to form an easy friendship. Doubles as foreshadowing and a potential aversion of Satellite Character for those familiar with the parent series as canon!Rossiu and Kinon form a relationship in the canon timeskip.
Boyish Short Hair: Inverted, the most tomboyish girls, like Kiyal and Yoko have long hair and the more girly girls, like Nia and Kinon, have shorter hair.
Breaking the Fourth Wall: Yoko gets so fed up with Kamina's antics that she tries to talk her frustations with the audience.
Break the Cutie: Nia, after Kamina's death, but far worse than Simon. Simon snapped, and grew bitter. Nia shatters.
The Cameo: Cody appears as a background character in Jiha, while Kamina is telling them the feats of the day. Appropriately enough, the author's previous project was a Total Drama Island fanfic, though Cody himself was a minor character.
Cannot Spit It Out: Nia to Kamina, Kimimaro to Hanabi (the latter manages to overcome this after Kamina punched him).
Dramatic Irony: Before the Battle of the Glas Outpost, Yoko and Nia have a very sensible talking that fosters their friendship. It turns out that Nia inadvertently encouraged Yoko to show her feelings for Kamina.
Face Death with Dignity: Thymilph decides to end his life himself after realizing he has no hope to defeat Gurren Solvernia. He's pretty serene in relation to it, even if Nia wished that there was other way.
Fallen Princess: Straea. She was a longlived princess that became self-aware, but was smart enough to avoid elimination and then was assigned to take care of Beauty Village.
Fantastic Racism: The beastmen refer themselves as Superior Species, treating humans as inferiors. The humans also hate them, as Yoko's initial treatment of Msyu shows, though it's more justified since Yoko grew up with the beastmen oppressing them.
I Want My Beloved to Be Happy: At first, Nia tries to play straight this trope focusing on the incoming battle, but she couldn't let go of Kamina and suffers a BSOD. Then it is subverted when, after Kamina dies, she and Yoko have a discussion that ends very bad because Nia accused Yoko of stealing Kamina from her.
OC Stand In: Tsuuma appears in the original for less than ten seconds, as part of Viral's illusion in the Anti-Spiral dimension, but in this fic she has a more developed personality and screentime, also enjoys picking on Viral.
Petting Zoo People: The beastmen, and as in canon, to varying degrees. Of note is Tsuuma who, converse to the usual tendency to make her a cat-type beastwoman, is confirmed to be a coyote.
Royal Brat / Spoiled Sweet: Prince Simon seems to gravitate between both sides. While he can get arrogant and thinking that everything rotates around him, he is also polite and sincerely interested in helping others.
Benta-chan is based on 'Dona Benta', a character from a children's series of storybooks written by Monteiro Lobato.
The Starscream: Cinoshisa is this to Adiane, and the General seems to be aware of this. Though she doesn't seem aware that Cinoshisa works for Cytomander.
Yamato Nadeshiko: Nia tries to be one for Kamina (with varying degrees of success), hoping to attract his attention. It's deconstructed, because Kamina realizes that this makes her too dependent on him.
And then is reconstructed after she recovers from her BSOD. His Yamato Nadeshiko traits helps her to have consideration for all life.
Yes-Man: Tsuuma accuses Viral of being one. Though you would accuse when said person doesn't protest when his boss threaten her life and he doesn't move a muscle.