I'm assuming that if you're reading this, you've seen the entire series of Tengen Toppa Gurren Lagann. I hope so - because I'm going to spoil pretty much everything about it in a minute. ;)
Gurren Lagann has a bifurcated story. The first sixteen of its twenty-seven episodes take place when the protagonist, Simon, is a young teenager. The final eleven episodes take place after a time jump of seven years.
I'm going to discuss what happens after the time jump. Before the time jump, for me, Gurren Lagann was a nice but rather ordinary shonen anime, complete with boy hero and mecha. Then came the time jump. And after the time jump, Gurren Lagann becomes something else again.
It's fantastic.
The final eleven episodes of Gurren Lagann take the story to such a new level, you wonder why the producers didn't start the time jump sooner. If all of Gurren Lagann had been of the quality that it is after the time jump, it would have been a shonen classic for the ages.
To begin with, Yoko becomes a more developed character after the time jump. In episode 21, we see that after the Spirals' initial victory against the Anti-Spirals, the sex-bomb with the big gun became "Yomako," a teacher in a rural area far from the big city - notwithstanding that she can pick up that gun again at a moment's notice to destroy massive enemy mecha that threaten her kids. ;) Yoko was a likable character before, but after seeing her as a teacher of small children and loving it, she's even more engaging after the time jump.
For me, the most interesting development in post-time jump Gurren Lagann is the changing relationship between Simon and Rossiu, who represent two different views on how to defeat the Anti-Spiral forces.
Rossiu initially belongs to an underground village that is ruled by a religious leader, who also happens to be his father. This group's edict, when more people are born than their resources can support, is to hold a lottery and send several people to the surface - to die, basically. Although he is only a boy himself at the time, Rossiu refuses to let two toddlers (Gimmy and Darry, who later become mecha pilots) who lose the (rigged) lottery be the only victims, and volunteers to go to the surface with them, knowing nothing about what's on the surface - except that no one ever returns from there. He is, in essence, willing to sacrifice his own life because he can't stand to let two little children die alone.
After Kamina's death, Rossiu becomes Simon's co-pilot in Gurren Lagann; and thereafter quietly fades into the background of the general mass of characters that populate the rest of the humans' crew for the remainder of the pre-time jump episodes. I was disappointed by this at the time, as I thought Rossiu was more interesting than that; but I only needed to be a little patient, as it turned out. ;)
Following the time jump, we see that Rossiu has become the head administrator of Kamina City, a position that eventually leads to near-dictatorial powers. He is also involved in a secret experiment to revive Lordgenome's brain in an attempt to discover more about the Anti-Spirals.
Rossiu is no villain; he's terrified that humans stand to be completely eradicated, and so he winds up making decisions that are brutal and exclusionary but that - in what appears to be an extreme, no-win situation - arguably make sense in sheer survival terms. I don't think we can fault Rossiu for not believing that Simon could triumph against impossible odds in stopping the moon from crushing the Earth; because this is what every other human on Earth is thinking, with the exception of Simon himself. He honestly believes that they can't save everyone; and the fear that all of them will be lost blinds him to the questionable morality of his decisions in acting to save just a few. Rossiu never loses his humanity throughout his time as head administrator, a fact that is made abundantly clear from his reactions of guilt and even tears when he thinks about some of his actions after the fact.
When Rossiu goes into a funk after Simon saves the world again, to the point where he is about to take his own life, Simon shows up and gives him the Magical Punch of Awakening! as Kamina had once gifted him with. As we saw with Kamina's earlier act, only worthy people get the Punch of Awakening ;) - so Rossiu is deemed worthy, as well as redeemed by Simon's act.
Simon also seems to lose his way after the Spirals' initial victory against the Anti-Spirals. He's given a high position in government, but doesn't appear all that motivated. It's only when the human population reaches a million and the Anti-Spirals become an active threat once more that Simon comes to life again to face the challenge.
Simon, of course, is the ultimate Spiral energy representative, carrying on Kamina's legacy as the one with heart and mojo and the juice to power the Spirals' fight to live. The bright-line contrast between the Spirals (representing desire for life) and the Anti-Spirals (representing the reactionary response and anti-desire) makes for an epic multi-episode climax for Gurren Lagann, a true adrenaline rush of an ending worthy of all the superlatives fans have heaped on it.
At the end of the series, in the "what happened to them afterward" sequence, we see that Simon wandered the earth with Boota after saving the world and losing Nia. It's an odd end for Simon, who - to be honest - doesn't seem deep enough as a character to be given such an introspective fate. ;) It could be that an older Simon as wandering hermit is a logical end for a shonen hero who has nothing left to sacrifice himself for. It's perhaps one answer to the question: where do old shonen heroes go to die?
The only reason I give Gurren Lagann a 9 and not a perfect 10 is because Simon is never sufficiently developed as a main character needs to be. Look at the difference between Simon and Naruto, for example. If Simon had been given a more interesting personality and a deeper backstory, Gurren Lagann would have been incredible. As it is, it's still a wonderful shonen anime with hugely thrilling moments; and absolutely worth watching all the way through to get to the best eleven episodes of the whole thing.
