Gurren Gakuen Hen

To promote the theatrical release of the first Gurren-Lagann movie, they released an alternate reality manga series that changed the setting to a high school (somewhat in the vein of Angelic Days). The manga pokes fun at the original series and high school manga in general.

Notable Differences

 * No Gunmen.
 * The concept of Nia and Simon 'combining' by holding on to each other, which gave Simon the power to defeat Viral instead of fighting him on his own in the anime.
 * Nia has an evil split personality (Parallel for Nia after being controlled by Anti-Spirals).
 * Lordgenome is an overly loving father figure that spoils his daughter and thinks no one is good enough for her.
 * Rossiu is an adult while Simon is a kid.
 * Kittan runs the Gurren Gang, While Kamina is in a separate group consisting of; Himself, Simon, Yoko and later on, Nia.
 * Kittan is somewhat an antagonist is this series as oppose to being a comic relief/secondary character in the anime.
 * Simon (at least with Nia) actually beat Viral in this manga. However, in the anime, Viral outmatched him.

Characters
Simon - An orphaned boy who just wants to live a "very normal life." Falls in love with Nia.

Kamina - One of the Great Banchou of Gurren High School, a strong believer in a man's soul, never enters Simon's room through his door, one of Simon's childhood friends.

Yoko Littner - One of Simmon's childhood friends, sees Simon as a little brother, strong fighter of Gurren High School. Often carries a a spear on her back in a bag.

Nia - Daughter of Lordgenome, rebelling against her father because of his oppressive behavior, is very innocent, also follower of a man's soul (a book both she and Kamina have read) and has an evil alternate persona

Rossiu Adai - Class president, takes class seriously, manages most of the day to day going-ons at Gurren High school.

Kittan Bachika - Leader of the Gurren Gang, fights Kamina often and has issues with the concept of marriage because of Kiyoh very young marriage.

Leeron - Dean of the School, very feminine.

Dayakka - Teacher at the school who is actually married to an underaged student, Kiyoh.

Lordgenome - Principal of rival school, Tepplin High. Over-loving father that metaphorically caged up his daughter and does not understand it is his fault for his daughter's mental illness.

Viral - one of Lordgenome's students, his job is to protect Nia, which he failed at a few times, was held back for a year for failure.

Four Beast Generals- All were Banchou at Teppelin High hired to capture Nia, all were subsequently defeated (Adiane by Yoko, Thymilph and Guame by Guame's exploding watermelon plan backfiring, and Cytomander being attacked by a Shark as he looked on the others claiming he will win).

Trivia

 * Only one volume exists