Tengen Toppa Gurren Lagann: Gurren Gakuen-hen (天元突破グレンラガン −紅蓮学園篇−) To promote 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.
- 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. His over-protection led to Nia being isolated and the development of her other side.
- Rossiu is older than Simon.
- 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.
- Simon - An orphaned boy who has been born with a notorious streak of misfortune and out of response, seeks a quiet and 'very normal life.' Childhood friends with Yoko and Kamina, the former trying to look out for him with the latter being the brother figure that he is. Falls in love with Nia, which helps him move forward.
- 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. He has great faith in Simon and hold a soft spot for Yoko. He later takes Nia under his wing.
- Yoko Littner - One of Simon's childhood friends, sees Simon as a little brother and argues with Kamina because of his strong-headness. She is strong fighter of Gurren High School. Often carries a spear on her back in a bag and seems to like Kamina back.
- 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 goings-on at Gurren High school. Has a very reflective forehead.
- Kittan Bachika - Leader of the Gurren Gang, fights Kamina often and appears touchy on the subject of marriage, a result of Kiyoh marrying Dayakka.
- Leeron - Dean of the School, very feminine.
- Dayakka - Teacher at the school who is actually married to an underage 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 at the others claiming "I will not be attacked by a shark").