Dust was all Izuku could see for miles, nothing but a grey desert that was only now beginning to settle. It had been a rough few days for Izuku; when everything was turned to dust, he seemed to be the only thing unaffected. His quirk had spread rapidly, crumbling everything—the buildings, the people, the trees, everything, except him, it seemed. "Some hero I turned out to be, I couldn't even stop that thing while it was at my feet, battered and bloody,"

At these words, a spectre of Toshinori Yagi, a gruesome visage to those who don't know him but a comforting sight to those who do, appears next to Izuku and takes a seat, not so subtly telling Izuku to do the same. "Midoriya, my boy..." Toshinori began to say, only to be interrupted with a shout,

"DON'T MY BOY ME!!... I don't deserve it." The last part was said in a whisper, but it was still heard anyway,

"Of course, you do. You know, I saw you as the son I never got to have, and I am so proud of how far you have come in such a short time." Toshinori tried to put his hand on Izuku's shoulder, but it went straight through. "Still not used to that,"

"But I failed, not just once or twice but so many times. How many times did I have the opportunity to kill that thing before it could do this?" Izuku stated with a hollow look in his eyes.

"You couldn't have known, no one could have," Toshinori spoke with a comforting tone.

"But I did, in a way, it's so obvious that's why I fought it alone, we knew it would lash out even after being beaten, we thought it would affect a couple of streets, maybe a small town at most... not this."

As Izuku spoke those words, a sudden epiphany struck Toshinori. "You... were ready to die, weren't you?"

With an almost guilty expression, Izuku spoke slowly, "I was. I even plucked a hair and gave it to Kacchan so he could train the 10th in my stead, a fat load of good that did now, I'm the last survivor of planet earth, and all."

"How did you survive? We are still trying to figure it out." Came the questioning tone of Nana Shimura, who appeared on Izuku's other side.

"It's simple, really. I jumped to reach it before it could use that damn quirk." Izuku spoke, looking into the confused eyes of the woman who reminded him painfully of his own mother.

"I don't get it?" Nana stated, which Toshinori agreed with a nod.

"Seriously, didn't one of you listen to my explanation of DECAY?!" Said a rather miffed Izuku.

"For the sake of the agreement, let's say no," Nana spoke with a slight blush on her cheeks.

Taking a deep breath, Izuku explained slowly, "Decay is a five-point activation emitter quirk that allows the user to destabilize large molecular structures, causing them to break down into smaller ones, losing their cohesion. Due to this nature, it cannot affect or pass through smaller molecules such as water and the various gases in the air, or else I would be dusted as well, alongside the atmosphere and anything in the water. Does that clear things up for you?"

At the end of the explanation, a thoughtful look came across Toshinori's skeletal face. "Say, young Midoriya, you said the quirk can pass through air or water, didn't you?"

"Correct,"

Toshinori replied, "And you said that you were unaffected because you were in the air?"

"Yes," Izuku quickly answered.

"And how many people are usually on the water and in the air at any given time?"

With this statement, a spark of hope entered the young boy's eyes as he gave the admittedly simple answer, "millions."