World of Spiral

The World of the Spiral Uprisings, where a battle between the beings of Spiral, capable of evolution, and the Anti-Spirals, beings who fear and oppose those of Spiral.

Humans

Humans are a Spiral species and the central race of beings in the universe of Spiral. Prior to Lordgenome's reign as the Spiral King, Humans were the leading Spiral Race who flourished unashamedly on their power forging numerous cities, spiral-powered mechanisms and large scale spiral constructs across the face of their home planet, Earth. In the heat of their progression, humanity was attacked by the Anti-Spirals, a race of stasis-based beings who had set their sights on Earth, having made it their purpose to obliterate the growth and progression of the Spiral by any means necessary including mass genocide.
In the wake of the attack, a particularly strong Spiral named Lordgenome, who would go on to become what was called a "Spiral Warrior" or "Spiral Knight", discovered a mini-gunmen that would be the foundation for humanity's strike back against the Anti-Spirals. Piloting the mini-gunmen in a torrent of Spiral power, Lordgenome led humanity into battle with an army of gunmen, the representative weapon of the human race, many topped with a head similar to the mini-gunmen found by Lordgenome himself.
Lordgenome came to be called the "Spiral General" and captained humanity's Spiral flagship, a gargantuan moon-sized space vessel titled the "Cathedral Terra". Over the course of Lordgenome's life, humanity and their legions of Spiral Knights engaged in sustained combat with the Anti-Spirals and despite their losses to the various plots and dangers thrust towards them by their adversaries, they continued to persevere under the Spiral General's lead. Perhaps one of their most tragic and iconic losses was at the hands of theDeath Spiral Machine, a colossal mechanism created by the Anti-Spirals to convert all Spiral Power into dense space exponentially faster than it could be produced, resulting in all spiral life-forms being left drained and lifeless in the sea-like expanse.
Many Spiral Warriors fell victim to this device in their attempts to reach the Anti-Spiral homeworld. Throughout their many losses and setbacks at the hands of the Anti-Spirals, gunmen upon gunmen torn asunder, neither side showed any true signs of stopping their assault or halting their efforts.

The Fall of Humanity

It was later that Lordgenome was visited by the Anti-Spiral itself, the hive-mind manifestation of the collective wills and consciousnesses produced by the Anti-Spirals, and was told the true reason behind their actions. At a loss and thrown into complete despair after gaining knowledge of what the Anti-Spirals had dubbed the "Spiral Nemesis", Lordgenome sided with the Anti-Spirals and turned on his brethren, obliterating them with murderous ease.
The remaining minuscule traces of humanity would be chased and herded underground, forced to live out their lives in secluded villages while "Beastmen", animals mutated by Lordgenome, piloted gunmen across the face of the earth in order to both exterminate any humans on sight and maintain the terror driven status-quo.

Beastmen

Beastmen are a blend of human and animal DNA, varying greatly in appearance; some are almost completely humanoid, while others are entirely inhuman-looking. These hybrids served Lordgenome, their creator. They cannot produce Spiral Power and, as such, do not set off the Human Extermination System set up by the Anti-Spiral. They also cannot reproduce and need coma-like sleep to stop from cell degeneration, unless they have an immortal body like the one given to Viral. Due to their inability to produce spiral power, they pilot Gunmen by using solar powered batteries, which prevents them from operating at night. However, larger Gunmen (such as Dekabutsu or the hot spring gunmen) can supply smaller ones with power, allowing the Beastmen to work at any time of the day.
They do not like humans and see themselves as superior to them because of their rule over their Earth under the Spiral King, who had them kill any humans who made it to the surface. The Human Extermination Army was divided into 4 divisions, each ruled by a different Supreme General.
After Lordgenome's death, the Beastmen armies were disbanded and all Gunmen were scrapped. Many Beastmen living within Teppelin itself survived its collapse, and were persuaded by Nia Teppelin to accept peace with the human victors and were integrated into Kamina City's society without prejudice. On the outskirts of civilization, liberated Beastmen warlords continued to wage campaigns against human settlements, so battles between the New Government and Beastmen erupted over time. Seven years following the Battle of Teppelin, few if any of these resistance forces remained, most having been eliminated by Grapearl squadrons.

Spiral Power

Spiral Power (螺旋の力, Rasen no Chikara) is the primary power source of all Spiral beings and primary theme of Tengen Toppa Gurren-Lagann. Not only is it the basis of strength for the main characters and all of mankind, but it is presented as a philosophy and a model of physics.
In the series' concept, Spiral Power is the power of evolution, generated by beings capable of doing so, like humans and other DNA-based animals, whose spiral double helix molecular structure allows them to get stronger through the generations. Spiral Power is what connects spiral beings to the universe and is produced by the energy generated by gametogenesis in living creatures to keep evolution moving forward. Beastmen, because they do not reproduce naturally, cannot evolve, thus are unable to produce Spiral Power. The amount of Spiral Power produced by an individual may vary and is based not only on its own limitations, but also its immediate will to survive and persevere.

Spiral Power has both infinite potential and applications - it has been known to regenerate and grow new parts on machines to a galactic scale, and even create tunnels through spacetime. One of its most prevalent applications in the series is in weaponry: Spiral-enhanced ammunition provides phenomenal stopping power, making a simple shotgun capable of damaging a Mugann, while Spiral-based warheads and energy beams demonstrate destructive power far in excess of nuclear weapons. Another hypothetical application mentioned by Gimmy in the final episode is the power to resurrect the dead, the only possible proof being when Kamina reappeared to break Simon and Yoko free of their dream-mazes. However, Simon and Leeron rejected the idea, seeing it as a hindrance to the future.

Lordgenome, whose own name contains the word genome, referring to DNA and its spiraling double helix, notes that it is the natural order of the universe to coordinate itself into a spiral arrangement. The spiral symbolizes the double helix structure of DNA, representing biological evolution, and the spiral structure of a galaxy, representing universal evolution. Simon's spiral drill is used as a motif to symbolize the spiral theme throughout the series. At the same time, the drill motif symbolizes the strength to challenge or 'drill' through tough and insurmountable obstacles. This philosophy is defined by Kamina as one's "Fighting Spirit" and by believing in themselves and others, they can "Kick logic to the curb and do the impossible."

In the same way a logarithmic spiral grows in size with each successive curve, the scope of Gurren Lagann's story and the scale of its mecha grow in successive steps as the series progresses. By the end of the series, the largest mecha, the Tengen Toppa Gurren-Lagann, contains all the smaller iterations of Gurren-Lagann nested inside like a matryoshka doll, reflecting the way the curves of a spiral grow in size but maintain the same shape.

Every non-Beastmen character is capable of utilizing their spiral power in some way, however there are only a few known characters that have fully unleashed or awakened their spiral powers in the story line: Kamina, Simon, Kittan, Boota, Lord Genome, and the collective consciousness of the Anti-Spirals.

Anti-Spirals

Spiral Power is specifically stated to defy conservation of energy, which in addition to explaining the creation of mass that is practically constant during battles, also carries danger if Spiral Power is overused.

Eons before the story begins, a certain race evolved enough to prosper across the stars through the use of their Spiral Power. However, discovering that the limitless evolution and power could one day lead to the destruction of the entire universe, an event they termed the "Spiral Nemesis", they abandoned the use of Spiral Power and sealed their bodies on their home planet, ceasing to evolve, and calling themselves the Anti-Spirals.

As the name implies, they also acted to repress other civilizations that used Spiral Power, fearing that they could also become a threat to the universe if left unchecked. Since Spiral Power comes from the will of its users, the Anti-Spirals tend to employ tactics specifically designed to induce fear, despair and hopelessness in their enemies. The Anti-Spirals also tend to spare their enemies if they surrender, but leave behind automated "defense" systems that will activate and attack a Spiral civilization if it grows too strong.

Since Spiral Power comes from willpower, it can be assumed that the equivalent creation was their embodied consciousness, the Anti-Spiral, who is the one that actively leads their army.

Trivia

• Spiral Power takes direct inspiration from the Getter Rays of the Getter Robo Saga, serving the same purpose of evolution of lifeforms, and being primarily green in color.