I don't understand, why can't I remember? || Demon Slayer

Forgotten

Akaza was tasked to visit the entertainment district, where the 6th uppermoons dwell.

The sun goes down, as the moon rises. It was time for the demons to wander around, hunting for their prey. Akaza arrives at the district, people would give him weird looks, so he decided to avoid the crowd, since the clueless mortals will just judge him and waste his time. The night Akaza came was coincidentally a special night, a night he would not have expected. The crowd talks loudly as Akaza walks at the roofs, upper 6, Daki recognizes his presence and she goes out as well to greet him. "Hello Akaza, ate any humans today?" Daki asks, Akaza did not answer as Daki acts very childish, "ugh, you're boring, but I'll be nice to you since we're comrades." Daki replies as Akaza did not reply once again. "You know, there'll be fireworks later, check that out if you want." Daki mentions before she leaves and goes back to where she came from. Hearing this, Akaza felt his head hurting.

"if we can't go this year, we can next year or the year after that."

He heard a whisper, a whisper that sounds like his own voice. More calm, with a soft tone. What the hell? He thought. He was confused as he held his head and hit himself. Control yourself Akaza, this is just some useless thing. He tried to tell himself it's just nothing over and over, but he cannot stand the voices. He was standing at the same spot for minutes, that was until his body dragged him somewhere. He didn't move willingly, it was like his body was walking to see something without the brain knowing. His body stops as he is in a high platform, seeing the beautiful night sky. The people were happy, the people were loud and excited.

Then the fireworks set off.

Akaza was unexpectedly addicted to this.

"Kyoyu...Kayi.... No no... It's...

Koyuki?"

He remembered. He said her name. A piece of his fiance still exists in his memories. He remembers a bit now. He is still confused, but he remembers the times they were together happily, before he lost his mind.

"if we can't go today, there's next year and the year after that. We can just go then."

"Do you remember talking about seeing the fireworks when we were kids?"

"I love you, Koyuki."

"I love you, Hakuji-san!"

"AGH! STOP IT! NO- I DON'T WANT TO REMEMBER!" Akaza yells at himself, he cries as he hits his head multiple times. "Why... I'm sorry I wasn't able to save you Koyuki... Why was I so useless? Why?" Akaza mumbles as vision turns black, seeing Muzan right in front of him.

"T H A T  I S  E N O U G H  A K A Z A. D O N ' T B E  A  W E A K L I N G." Muzan yells at Akaza as Akaza cries. "Right, apologies master." Akaza wipes his tears and pretends nothing happened. His emotions are caged, and his memories will still be forgotten and uncovered.

"I understand why I didn't go with Keizo, and Koyuki. I understand why I deserve to be in hell. I was a monster."

That was his words in the afterlife.
Koyuki's spirit has calmed him down, but does he really forgive himself?