Episode 24

"Past the Infinite Darkness" is the 24th and final episode of Kill la Kill.

Paralyzed
Ragyō Kiryūin uses the power of her Shinra-Kōketsu to negate the effects of everyone's Kamui and Goku Uniforms. Aikurō Mikisugi and Tsumugu Kinagase attempt to fight Ragyō by combining their DTRs into one mecha, but Shinra-Kōketsu blows them away with ease. Nui Harime wonders why Ragyō doesn't just kill their foes, but the REVOCS director explains that they will make "excellent fuel" for the Original Life Fiber. Using Shinra-Kōketsu's power, Ragyō revives the fallen Original Life Fiber and summons it to Honnōji Academy to envelop the gathered students.

In an impressive display of will, Ira struggles to reach Ragyō while carrying his fellow Elite Four members and Mako. Nui mocks their efforts, but Mako Mankanshoku manages to dislodge herself from Ira Gamagōri's back and defy the Grand Couturier, declaring that the bond between Ryūko Matoi and Senketsu is proof that humans and clothing can coexist peacefully. Tired of Mako's speeches, Nui transforms her arms into blades and attacks, only for Gamagōri to block the blow with his own body. With the last of his strength, Gamagōri declares his intent to protect his fellow students before hurling Nui away and seemingly dying.

Hybrids
As Mako and the other members of the Elite Four mourn the fallen Gamagōri, Nui returns to the tower and prepares to resume her assault. However, Ryūko steps up to fight without Senketsu, revealing that her combination of human and Life Fiber physiology renders her immune to Shinra-Kōketsu's Absolute Domination. Nonetheless, she is quickly overwhelmed by the empowered Ragyō. While Senketsu tries to resist Shinra-Kōketsu's power, he discovers that Satsuki is also capable of hearing him. With Ryūko defeated, Ragyō attempts to fuse everyone into the original Life Fiber; but Senketsu, acting on his own, manages to pierce Ragyō's body and dislodge Rei Hōōmaru, restoring everyone's power. As he fuses with Ryūko, Senketsu explains that he is also a human-Life Fiber hybrid, which he realized when Satsuki heard his voice.

With their resolve and ability to fight back restored, Ryūko and Satsuki—each wielding one of the Scissor Blades—deal a critical blow to Ragyō. Meanwhile, the Elite Four lead the charge against the satellite uplink Ragyō needs to engage the final stage of her plan. However, none of them can breach the barrier around the tower, and Nui sends her clones to further hinder their efforts. Suddenly, Ira drops from the sky, having survived Nui's attack by wearing steel armor under his uniform. To make up for making the others despair, Gamagōri uses his Shackle Regalia to tear the barrier open with his bare hands. After blasting a hole in the uplink's armor, Gamagōri makes way for Aikurō and Tsumugu to destroy the uplink, by self-destructing their mecha as it flies into the hole.

Ascension
Satsuki Kiryūin declares that Ragyō's plans are at an end, but Ragyō has one more trick up her sleeve. At her command, Nui decapitates herself—to everyone else's shock and awe—and fuses with the original Life Fiber. The combined being then merges with Ragyō, healing her wounds and allowing her to fly into space. Hōka discovers that Ragyō intends to activate the satellite directly, awakening the Life Fibers across the planet. As the aliens absorb their human wearers and form a cocoon over the Earth, Ryūko absorbs the combined power of Senketsu, Junketsu, and all of the Goku Uniforms within Honnōji Academy to form Senketsu Kisaragi, launching into space to face Ragyō.

Endgame
Mother and daughter begin a furious battle, with Ryūko seemingly unable to defeat Shinra-Kōketsu's raw power. The situation seems hopeless, especially when Ragyō discards the last of her humanity to unleash the full power of her Kamui with only Ryūko's supernatural regenerative powers stave off death at her demented mother's hands. However, Ryūko reveals that she has been willingly taking Ragyō's attacks to provide Senketsu with the power needed to absorb Shinra-Kōketsu itself. Using the ultimate Kamui's "Absolute Domination" ability, Ryūko commands all Life Fibers across the Earth to release their trapped humans, declaring that "humans are humans and clothes are clothes".

Farewell Descent and Epilogue
With humanity saved, Ryūko tells Ragyō to come quietly back to Earth. To Ryūko's surprise, Ragyō instead pulls out and destroys her own heart, after gloating that the Life Fibers will one day return to Earth. As Ragyō disintegrates into her component Life Fibers, Seketsu interrupts Ryūko's pensive pause. With the damage he sustained from absorbing Shinra-Kōketsu's power, Senketsu is now falling apart as well. Before Ryūko can comprehend the situation, Senketsu whisks her back towards the planet, using himself to shield her from the heat of re-entering the Earth's atmosphere. As Ryūko protests, Senketsu tells her that she has outgrown him—with the Life Fibers gone, she is free to wear whatever clothes she wants. Bidding Ryūko farewell, Senketsu burns away completely, the last of his Life Fibers disappearing in Ryūko's fiery wake.

Grief-stricken, Ryūko continues to plummet back to earth. Seeing her falling form, Satsuki screams at Ryūko to hang in there as she runs full speed to catch her. With the help of the Elite Four, the Mankanshoku family, and essentially every other character, they manage to divert the force from Ryūko's descent from vertical to horizontal—sending them all sliding backward into the school building with a loud crash. Once the dust settles, Satsuki gives Ryūko, who calls her "Sis", a warm welcome home.

With the world freed from the threat of Life Fibers, Ryūko begins a new life with Mako and Satsuki, keeping the memory of Senketsu in her heart as the world moves forward into an age of freedom.

Characters

 * Ryūko Matoi
 * Satsuki Kiryūin
 * Mako Mankanshoku
 * Senketsu
 * Junketsu
 * Ragyō Kiryūin
 * Shinra-Kōketsu
 * Ira Gamagōri
 * Hōka Inumuta
 * Uzu Sanageyama
 * Nonon Jakuzure
 * Nui Harime
 * Rei Hōōmaru
 * Aikurō Mikisugi
 * Tsumugu Kinagase
 * Mankanshoku Family