End of despair

Sunshield: "Stop right there! You're disturbing the civilians!"

Kanata places a hand on her shoulder.

Kanata: "Step away. I'll take it from here."

Sunshield: "P-Phy?! They are just some troublemakers... I can handle this."

Kanata: "They're not human. Please, just don't escalate this further."

Sunshield: "U-Understood."

She bows to Kanata.

Sunshield: "Forgive me for doubting you, Phy."

She leaves.

Kanata: "Some of the power I acquired in that timeline is still with me... But I can't let them suspect that something happened."

Zetsu: "Ho... So you already knew we were here."

Kanata: "I have a proposal. Leave my planet out of this."

Lust: "Oh, that's a great idea!"

Zetsu: "Why? Not that I have any other business here besides you, but..."

Lust: "Come on, Zetsu, leave this planet to me!"

Zetsu: "Whatever. My friend Lust will protect your little planet while we fight."

Kanata: "How can I be sure he won't kill anyone?"

Lust: "Just so you know, I love humans. I won't let them die so easily."

Zetsu: "He's a bit weird, but he knows how to protect what he loves."

Kanata: "Alright... then let's go to-"

Zetsu: "Nah ah. I'll choose our first arena. Lust, take us to Mars."

Lust opens a portal behind the two.

Kanata: "What? Mars is too close!"

Zetsu: "Huh? Are you saying you're strong enough to affect Earth from there?"

Kanata: "Not yet..."

Zetsu: "Relax, Lust will protect this planet from debris. Plus, if you kill me, he'll help you rebuild your solar system. We're gods after all."

Kanata hesitates, but stepped through the portal. They were on top of Olympus Mons, the largest volcano in the solar system.

Zetsu: "So the rules are simple. I won't kill you until you reach close to my level."

Kanata: "What about turning me into a vessel?"

Zetsu: "I'll decide that based on your performance."

Kanata concentrated. She began to increase her body temperature and gravity. After a few seconds of staring at each other, she took the first step. She leapt towards Zetsu with a punch, which she dodges. Then, she dashes again, and again, and again, each time faster than the last.

She began to approach the speed of light. The two of them moved so fast that time began to distort. Kanata managed to land a blow on Zetsu, who blocked it with both arms. The shockwave instantly vaporized Olympus Mons and shattered Mars. The planet's core released magma towards where they were. Kanata flew until she reached a moon and kicked it towards Zetsu, who summoned her knight puppet and destroyed it with a punch.

The goddess picked up the debris and threw it at Kanata, who dodged and flew towards Zetsu, grabbing her body and dragging her away from the solar system. Zetsu's knight picked up Kanata and threw her towards Neptune. She fell into the dense, cold atmosphere, in the center of the Great Dark Spot. The intense wind pushed her away, the storms struck her with multiple lightning bolts. Her skin began to freeze.

Kanata concentrated again. She discovered another ability: increasing the electricity in her body. She mastered the power of electricity in just a few seconds. Zetsu punched her in the face, and then again as she flew. She kept throwing her body around as if Kanata were just a ping pong ball.

Kanata tried to punch Zetsu, who blocked each impact with her hands. The shockwaves dissipated the planet's atmosphere. Kanata kicked her downwards, towards the core. The planet exploded instantly.

Zetsu flew towards Neptune's moons and threw them at Zetsu, who blocked them with her arms. Then, she flew towards Mercury, summoned her knight and threw the planet at Kanata, who punched it. Zetsu appeared behind her and threw the debris towards her. She dodged, but then the goddess jumped from one debris to another, confusing Kanata.

She landed a kick to her back, launching her towards Jupiter.

Zetsu: "You're not the only one who knows how to improvise a weapon, kid."

Zetsu pulled out a strand of her hair. She held each end with one hand. Aiming at Kanata, she released it. It flew faster than light. Kanata's body vaporized instantly, except for her head. The strand hit Jupiter, exploding it.

Kanata lost consciousness until she was on the surface of a star. Zetsuheld her head until she threw it to the "ground".

Zetsu: "We're gonna speedrun your power growth."

Kanata felt immense pain, but her body was slowly regenerating, despite nearly melting. She unlocked a new ability: lowering her body temperature. When it was almost complete, she released a cold wind that nullified some of the heat from that star. Zetsu also froze, but then gave up the act.

Zetsu: "Let's see if you're cool enough!"

She shoved Kanata's head into the star, piercing it until she reached its core. Kanata began to melt, but then she grabbed Zetsu's neck and froze her for real this time. She released another cold wind that froze the entire solar system they were in. Exhausted, she still punched Zetsu until her body shattered. The goddess caught her fist and crushed it.

She threw Kanata's body in a seemingly random direction. As the human flew, the goddess aligned all the planets in that system so that Kanata could pass through them. After passing through all of them, Zetsu grabbed the enemy's neck and flew to another solar system.

She tossed her away and kicked some stars towards Kanata, who took major damage. She increased her gravity until all the planets and Zetsu were pulled towards her. She landed many punches and kicks, until Zetsu grabbed her legs and crushed them. She then punched Kanata towards another galaxy.

The heroine was pulled into a neutron star, forced against its surface. Her senses deteriorated rapidly. The light was so intense that her eyes became useless. Resisting the heat and gravity was exhausting. She remained standing until Zetsu summoned her knight to punch the star and explode it, releasing a supernova.

The shockwave sent them flying into another galaxy. Kanata landed in a black hole. She felt such immense pressure that she could no longer stand. Her body began to fall apart. Zetsu approached her and pierced her heart with the mystical knife.

Zetsu: "This is your time limit. If you die under the effects of this knife's poison, it's over forever."

Kanata tried to get up, but the poison grew stronger over time. Zetsu kicked her, toying with her. The heroine flew the goddess out of the black hole's range and then kicked her towards the black sphere with such force that the galaxy felt a slight disturbance in space. The impact was almost enough to open a portal to another universe. Zetsu's body passed through the black hole, dissipating it.

The light trapped in its orbit flew away, blinding Kanata. The puppet knight punched her, sending her hurtling toward a supermassive black hole far away. Zetsu followed suit and punched Kanata on the way. The heroine's temperature rose. Her aura turned into that of a neutron star. But it kept growing, until it exploded into an even larger supernova. Zetsu felt a slight damage.

This did not stop her from entering the supermassive black hole, exiting through a white hole on the other side of the universe. Zetsu launched a supermassive black hole at Kanata, causing her to teleport again. Then, the goddess merged two black holes, where the heroine was. Kanata, luckily, dodged the attack, catching Zetsu by surprise and landing a punch in her face before she could react.

The impact was so unimaginably powerful that the nearest constellation ceased to exist. Zetsu clutched her head, disoriented. Kanata was also hit by such force. The knight punched her, but she blocked it with another punch.

The shockwave caused the galaxy they were in to disappear. Both were cosiderably injured. Zetsu tried to stab her with the knife several times, but Kanata managed to grab her arm with the last picosecond. They began exchanging punches faster than the smallest unit of measurement of time. Each impact was enough to vaporize galaxies. The knight joined in and struck Kanata several times, then pierced her back.

Zetsu: "I'm not done yet, human. Do you still think you stand a chance against me?"

Kanata's body had a huge hole in the center. She was almost dead. Zetsu grabbed her by the hair.

Zetsu: "Do I look injured yet? I can heal, just like you. But infinitely faster and stronger. Get up."

Kanata grabbed her arm and crushed it. Zetsu writhed in pain and punched her so violently that the supercluster they were in was erased permanently.

Kanata lost her arms while blocking the attack. She flew as fast as she could, until she was out of the observable universe. Zetsu arrived and kicked her away, leaving that universe. Kanata's arms healed. They exchanged punches so fast that time itself could not comprehend the speed. The impacts grew stronger and stronger, until the knight and Kanata punched each other again. The range of the shockwave was comparable to that of the universe.

The knight, Zetsu, and Kanata lost their right arms. The goddess stabbed her a quadrillion times before she could even react. The poison became so strong that Kanata felt death.

Zetsu: "You can become a great vessel if you surrender now."

Kanata: "What's this...? I can't surpass her even with all this power..."

Zetsu: "What? Did you think you were the only one who could grow stronger? My power is indefinite, my dear."

Kanata: "What...? So, as a human, I never really stood a chance..."

Zetsu: "Taking damage is one way to get stronger. Dealing damage is another. So, stand up, let us decide the outcome."

It was all black. They were in an endless void, since everything was destroyed.

Zetsu: "You have no other chance. This is the last showdown."

Kanata: "I can't screw this up... humanity is my responsibility now."

Their bodies were already healed. Kanata concentrated. Even with the poison coursing through her body, she managed to breathe slowly and steadily. She was ready. It was now or never. She leapt forward.

Kanata: "Even if I die, I will eliminate her!"

They exchanged blows at... god, I don't even know how to describe how many attacks they unleashed in the smallest unit of time... let's just say they were so fast and strong that reality itself began to fall apart. The knight joined in and intensified the battle. All of their bodies began to shatter. Kanata punched the puppet's helmet and broke it, as well as part of Zetsu's head.

Just as Kanata got used to the speed, Zetsu decapitated her with the knife. 

Zetsu: "Ever since the beginning, everything was under control."

Kanata: "What...? Is this how I die...? This can't be possible... it can't... I have to do something... a last punch!"

She punched through Zetsu's head. The knight brought both his hands together where Kanata was, crushing her. The shockwave created another Big Bang, infinitely stronger than the original. Their reality vanished.

Lust teleported Zetsu to Earth, which was teleported by him to another dimension. She was exhausted and nearly dying.

Lust: "Everything was under control, huh?"

Zetsu: "Shut up..."

She fell, bleeding and unconscious.

Sunshield: "Who won...?"

She was sitting next to him, seemingly comfortable.

Lust: "Kanata is dead."