Tower of God!AU with my own twist.

Spoiler free~!

P.S. The OSTs are sick!

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—Headon, Tower of God

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Climb the tower and everything will be yours.

Tanjirou doesn't need that. He doesn't climb the tower for his sake, for his everything. So, he trudges, walks, and suffers through the test.

Surviving through the purgatorial tests until now was a miracle for Tanjirou.

He never expected to come this far, judging by how cruel the first test when he first came. Killing everyone until it reaches to a specific number of people. It's cruel and harsh for him. It's too much.

But, he has to endure all of this to get his family back. It's the only way to save them. Climb the tower and bring his family back.

There's (Y/N). She had been with him through thick and thin, ever since the second test where they had to from groups of three. She had always been mysterious, yet her welcoming and ambient attitude pushed all of his suspicions away.

Tanjirou asked her one time, "Why do you climb the tower, (Y/N)-chan?"

A smile ghosted her lips. "I want to see what the tower looks like. I want to know why people climb the tower."

At first he was taken aback, who, in their right mind, will come to the tower just to check it out? It gave him chills. She returned the question, "How about you? Why do you climb the tower, Tanjirou?"

His hand fiddled with the earring from his father. "To bring my family back."

Her hand reached out to place over his, an attempt to soothe his nerves and to offer a silent sanctuary amidst his grieving feelings.

She said, "We'll climb the tower together, until to the top."

Tanjirou spent the following weeks in the tower, hanging out with Zenitsu and Inosuke. The three were almost inseparable. Even so, Tanjirou always found himself staring at the simple girl hanging out with Kanao with the slightest curl of her lips.

Tanjirou knew they are fated to be enemies, but he couldn't but help that tiny string of hope in her words.

"We'll climb the tower together."

It's a good dream alright.

* * *

Tanjirou thinks he won't survive this test.

But, he made a promise. To her and to himself. He'll pass this test and he'll save his family. He'll pass and see her smile when he sees her alive and well.

He promised they'll climb the tower together.

He promised and he had to do his best fulfilling it.

So, why won't his body move?

Tanjirou's body was frozen still and rooted on the damp grass. His eyes held one of fear and he couldn't shake the feeling of being the prey. He could almost hear the grim reaper calling for him or maybe had his scythe on his neck. He was dreading. Is this the end?

In this test, no one is spared from a gruesome death. He could even hear the screams and shrieks of horror of others with him. With man-eating demons lurking so freely in their testing area, he doubt he'll come out as the same person again.

He gripped his weapon—a katana given by Giyuu, their test facilitator. If Tanjirou dies now, he'll never be able to bring his family back. It will be his endpoint.

Tanjirou barely missed his death as the demon lunged at him with lightning speed.

He raised his blade. "I'M GOING TO SEE MY FAMILY!"

Tanjirou lunged at the Herculean demon, hands gripping his katana tight. His swing was avoided easily. His heart dropped. Tanjirou could see the demon's fist coming at an alarming speed. There's no time to dodge it.

The fist was covered by blizzard, stopping merely inches from his face. His legs gave up beneath him and collapsed. His eyes wandered to the demon, now engulfed in ice. The cold replaced the warm air, sending shivers down his body.

Tanjirou wasn't given another moment to recover before the statue of blizzard cracked. He was about to bolt away from the frozen demon when it broke into tiny millions of pieces. The ice was reduced to cold dust in that moment.

"I understand now." Her voice was calm and composed. Tanjirou scrambled to stand. He faced her. She had a soft smile on her features. He noticed the weapon in her hand. It was far too beautiful and it looked too powerful. Is she the one who just froze the demon and reduced it to pieces? She's powerful, so powerful.

"(Y/N)," Giyuu called out her name, appearing not far behind her. "Your actions are not allowed in this tria—" Giyuu cut himself off at the sight of her weapon.

"Is that the Merciful Winter?" Giyuu had heard of the weapon relic and saw its form in books , yet he never witnessed it in his whole time in the tower.

If she has it, then there's only one true fact about her. It can't be, right? There's no way for a being like that to be here, submitting to the tests of the tower.

She answered, "Yes, Giyuu."

The vigor in her voice is something that should not be mistaken. Only one person can wield the Merciful Winter so majestically.

Tanjirou watched with wide eyes to see Giyuu kneeling on one knee. His head down with humble and respect. She only cast a glance from the corner of her eyes.

With reverie, Giyuu greeted, "My Goddess. It's an honor to grace us with your presence."

She didn't pay much attention to Giyuu as her focus was solely on Tanjirou.

She asks, "For what do you risk your life to climb the tower, Tanjirou?"

Tanjirou answered, "To save my family."

"Is that all?"

"Yes."

She extends her hand to him, waiting to be taken.

"Then, I shall take you to the top of the tower."