This is something I've put some thought into. There are numerous fanfics where DBZ Bad guys become good guys, such as Break through the Limit and Honor Trip. This fic is meant to be similar to those. I mostly wanted to get those out at some point.

With that said, enjoy!

Mr. Popo had considered his wish carefully. Originally, he had only come to revive everyone who had died on Namek, but then he considered something else: what about all the people who had been killed earlier by the Saiyans? He only had one chance to revive them, otherwise they would be permanently killed. He wasn't sure if Shenron would be able to revive all those killed on Namek and Earth, but if there was the chance...

"Shenron, I wish for all those killed by the Saiyan invasion on Earth and by Frieza and his minions on Namek to be revived," Mr. Popo asked.

The dragon's eyes lit up for some time, before they returned to normal, "You're wish has been granted. All those killed by Frieza and his men on Namek, and those killed by the Saiyans on Earth, have been revived."

The Eternal Dragon disappeared, and the dragon balls scattered across the globe once more.

In a distant desert

Tien Shinhan and Yamcha both found themselves in the desert where they had died. The two human warriors were both glad to be alive, though they soon realized they were apparently the only two Z-Fighters in the desert.

"VEGETAAAAA!" someone shouted. The two humans both turned toward the distance and sensed the enemy's power. A familiar foe who had become stronger.

The Saiyan warrior Nappa, the one who had killed both of them before. The two human warriors rushed to meet the Saiyan and stop him if necessary. Once they arrived, Nappa looked up into the air, a bewildered look appearing on his face.

"What the-? How are you alive?" Nappa exclaimed, "No matter, you guys won't stop my revenge against Vegeta."

"I thought you were friends with Vegeta?" Yamcha asked.

This was apparently the wrong thing to say. Nappa got an angry look on his face, before he flew off into the distance.

"Where are you going?!" Tien questioned.

"I'm going to kill Vegeta!" Nappa replied.

"He's not even on-," Yamcha began, before Nappa flew off into the distance.

"Should we go after him?" Yamcha asked.

"He's stronger than before, but he's nowhere near the Ginyu Force's strength. If it comes down to a fight, then we can take him," Tien replied.

The two humans flew after the bald Saiyan, catching up to him soon after.

"What the!?" Nappa asked.

"Vegeta's not on the planet," Tien responded, "he was defeated, but Goku let him go."

"Feh. Where's Kakarot?"

"He's not on the planet either."

"Then where's my space pod?!"

"Er... Bulma destroyed it," Yamcha responded sheepishly.

"SO I'M STUCK ON THIS PLANET?!" Nappa shouted, an aura of power exploding around him. His power had increased even further with his anger.

Tien and Yamcha prepared to fight Nappa, both expecting the Saiyan to make the first move. Nappa fired his Kappa, which Yamcha countered with a Kamehameha. Both were surprised to see that their beams clash evenly. Eventually, Yamcha's Kamehameha won out, blowing through Nappa's Kappa and hitting him directly. Yamcha closed in on Nappa, the two both attempting to hit each other. Nappa was able to break through Yamcha's defense, sending him sprawling back. The Turtle School student prepared his next attack, the Wolf Fang Fist.

Nappa was sent flying back by the attack, righting himself moments before he collided with a nearby cliff.

'How could I be losing to these humans?! When did they... they must've trained the same way Kakarot did...' Nappa thought to himself. He then began to power up, trying to call up any power he was holding back.

Nappa was about to charge at the two humans when he suddenly sensed a massive power-level approaching. He'd never been able to sense powers before, but while he hadn't paid much attention to it against the two humans, the massive power level that was approaching completely overwhelmed him. He looked in the direction of that massive power and noticed the Namekian that he fought before.

"It seems Mr. Popo made a mistake," Piccolo stated.

"How are you alive?" Nappa asked.

"We were all revived with the Dragon Balls," Piccolo responded.

"But I killed you, I thought the Dragon Balls stopped working!"

"I was revived with the Namekian Dragon Balls."

"So why'd you revive me?"

"Mr. Popo made the wish to revive everyone on Earth who was killed during the Saiyan invasion. Maybe I'll fix that mistake," Piccolo stated darkly. Though Nappa had killed Piccolo before, he knew that now Piccolo was far stronger than him. If Piccolo wanted him dead, then he couldn't stop him.

"Hey Piccolo, maybe we should keep him alive," Yamcha said.

"Why?" Piccolo asked.

"Well, he doesn't like Vegeta. Maybe he could help out against him if he comes back?" Yamcha said.

"I think Yamcha has a point, if Vegeta decides he wants us dead, we'll need all the help we can get," Tien mentioned.

Piccolo seemed to spend some time thinking, before he replied, "Fine, I'll let him live for now. If he causes any trouble though, then he's dead." The Namekian flew away afterward.

With Piccolo's departure, Nappa was left with the humans.

"Well, if Piccolo says you're okay, then I guess you're fine," Yamcha stated, before he and Tien flew off, leaving Nappa alone with his thoughts.

The revived Saiyan began to consider what to do. If the Namekian was so far above him, then so were Kakarot and Vegeta. He supposed since these humans got as strong as they did, they'd be useful for getting vengeance on Vegeta.

Nappa surveyed the landscape and powered up. It was time to start training.

End Chapter 1

Nappa, Yamcha, and Tien are revived at the same time as all the Namekians, so this is taking place at the climax of the Frieza saga. Nappa only survived because of the humans vouching for him as well as Nail's influence in Piccolo's decision making. An unfused Piccolo would definitely have killed Nappa.

And some power levels, since people like those.

Nappa: 18,000 - With his revival, he's received a zenkai that puts him on par with Saiyan saga Vegeta. However, he's farther behind Vegeta and Goku than ever before. He's also gained the ability to sense power levels (hey, if Vegeta could do it, then so can Nappa).

Yamcha: 60,000
Tien: 65,000 - These take the events of the Human Z-Fighter vs. Ginyu Force filler to have occurred here. Tien is slightly above Yamcha, as he was able to fight both Burter and Jeice at the same time.

Nappa (enraged): 50,000 - With the combined anger from Vegeta's betrayal along with being stranded on Earth, he receives a sizable power boost.

Piccolo: 1,100,000 - Piccolo after fusing with Nail was capable of fighting evenly with 2nd form Frieza, after all.