Disclaimer: I do not own Db/Z/GT/Super. Not even a little bit.
I know this sort of story has been done before but this is my guess on what would happen.
This is a short tale, merely yet another of the "what-ifs". This one entails the battle between Frieza and Bardock in the upper atmosphere of Planet Vegeta. Just as Frieza is about to eliminate the chimps, behind his Death Ball a flash of Golden light, and the attack is dispersed. What has occurred, and what shall happen when Frieza finds out?
"FRIEZAAAAAAAA" The cry rang out into the upper reaches of the atmosphere, all of the PTO soldiers watched in awe as a saiyan stood against their lord. Bardock, the saiyan in question, looked absolutely pissed, in all sense of the word. He was exhausted after fighting through hundreds of troops to reach this point. No one made a move. Frieza rose a finger and a small orb of orange appeared just above said finger. He chuckled quietly to himself and as soon as Bardock threw his last hope, the last hope of the saiyans, the orb grew and expanded, easily overwhelming and consuming the measly attack. Bardock looked on with utter fear. He had failed, his people, his sons, and himself most of all. A saiyan warrior, one who could rival even the king, was about to fall against the tyrant bastard whom they have served. Bardock felt something deep inside of himself ignite, seemingly far off. It was pure rage, something Bardock and most other saiyans knew well, but this was.. Different. It was not wild, or predictable. It was calm, primal power. He almost felt fear of such a thing. But he reached deep into himself and grasped this foreign feeling, power.. It was powerful indeed. Bright and hot.. Something to feel in awe of. He pulled it forth just as the orange light of the Death Ball surrounded him and Frieza's laughter filled the skies. He saw a flash of gold and roared as his body was overwhelmed with a massive amount of energy. *
"HAHAHAHA! LOOK AT THEM ZARBON, DODORIA! SEE THE SAIYANS DIE NOW AND FOREVER- I...What in the hell is that thing!?" Frieza looked upon a warrior.. Wearing the same clothing and armor, even that stupid headband like the saiyan that attacked.. But this warrior was cloaked in golden light! His eyes.. A strange teal color! Saiyan's had black hair, and eyes!
"What is his power level Zarbon!" His order was responded to by a small explosion, as dozens of scouters blew up. This was odd.. That only happened when his own power level was scanned nowadays! What is this bull shit..
"I...AM A SUPER SAIYAN!" That voice.. Frieza levitated out of his hover chair. How dare this.. Chimp put on a light show and come to attack his lord! Frieza fired a death beam but this.. Super saiyan swatted it aside. It struck a soldier and pierced his chest. Frieza, for the first time in a long time, possibly ever, felt true fear. This was why he wanted to wipe these stupid saiyans out in the first place! Now, just as he is about to fulfill his plan, the super saiyan appears.. Damn him! Frieza charged forward, intent on ending this quickly, but his punch directed for the saiyan's gut was grabbed! Caught in Bardock's hand. Bardock looked at Frieza with a gaze the arcosian would never forget.. Frieza used his tail to knock Bardock back then rapid fired a blast at the warrior. Bardock was knocked back and Frieza rushed him as soon as he saw that the blast was knocked aside.. Right into a group of PTO soldiers. All of them were disposable. Suddenly there was the roar of battle cries and the two titans took a moment to look towards the planet, hundreds, no, thousands of saiyans were flying into battle against the PTO. Word reached them of the King's death at Frieza's hands, and they had seen the Death Ball from Frieza coming at them from above. Then, they were saved! By a flash of gold... Suddenly, all the saiyan's remembered what Bardock had said. Word spread quickly and the saiyans organized an attack, then charged into battle. Frieza looked to Bardock, who had a large smirk on his face, revelling in battle and the thought that the tyrant Frieza might fall this day. Frieza pulled the super saiyan from the thought with a fist slamming into his face. The two of them went at it again, Bardock smashing through the PTO soldiers as he flew by, Frieza doing the same with any pitiful saiyan who got too close. Soon a large area was cleared for the godly beings. The saiyans were invigorated by the rise of a Super Saiyan, Bardock, a lower-class of all saiyans! Frieza was infuriated! He had no chance to transform… damn this simian! He would make his death painful and graphic indeed! Strikes and blasts were thrown carelessly, each one meant to kill the target. Neither could accomplish this however. Frieza just needed a moment to transform… he rapid fired deathbeams, which were either avoided or deflected. Damn ape! Why won't he just die!? Frieza instead decided to pull a cheap move just after being knocked back. He looked behind the golden warrior a bright smile on his face.
"Father! Amazing how you arrived so quickly !" Bardock scowled and fired a quick blast at Frieza before turning enough to see behind him. Seeing no one he realizes that he has been tricked. Frieza has not attacked though so he turns to see Frieza.. Changing. His beat up armor is burst off his body, scouter long since discarded. He begins growing in size, obviously in power as well. Laughing the entire time Frieza finishes his transformation.
"Such a shame it came to this, you might have been a decent pet! But no, you had to rebel! Well, its time for your entire race to die. I planned on keeping that brat prince around as a trophy but no longer. I shall end the saiyan race, here and now! My powerlevel is over ONE MILLION!" Lost in rage and feeling more power than he had in a long time, he rushes Bardock and throws him towards the thousands of PTO soldiers and saiyans fighting. They all stopped to see what was happening, only to see a possibly insane Frieza gathering far more energy than that Death Ball had held. He wasn't going to wait for his people to move out of the way. Zarbon and Dodoria panicked, terrified. No one had seen this much power before. Bardock gathered everything he had and fired it at the same time as Frieza unleashed his hellish attack. Though this time his attack wasn't absorbed, it was losing too much ground. They were all going to die. Suddenly though, the saiyans began pouring their energy either into Bardock or his attack. Zarbon burst into his hideous form to help as well. Now the entire mass of PTO that were about to be killed by their evil ruler were putting everything on the line to stop him from killing all of them.
"OH!? A SLIGHT RESISTANCE!" Frieza pushed a bit harder, the entire saiyan race put forth all their strength with the PTO troops there, surely they had enough power, if Bardock was at least half as strong as Frieza was- but alas, he had lost too much energy during the fight against Frieza. It was not a winning battle as Frieza's voice, deeper now than in its previous form, laughed at the saiyans. Their pitiful attack finally was overwhelmed and Bardock lost his golden form. The despair from this, all the saiyans knowing their death was far more satisfactory than any surprise attack. There were no fireworks because his attack consumed the planet, as it was about its size, then dissipated in a simple wave of massive energy. Frieza didn't care if he had to fly back home, that was well worth the trip to personally wipe out those chimps. Now he gets to go home and tell daddy dearest of his killing a super saiyan. That also means getting to rub it in that prick Cooler's face. Speaking of which, he should power up to his true form before he is caught off guard. He overcame the minor pain and aches of transforming so much so quickly, but stretching a bit he noticed a ship ways off, about to make a jump to hyperspace. He smirked, it seems his brother was spying on him. Aiming, he shot an amazingly fast beam that tore through the ship, and in a moment it exploded. A form rushed to him, glaring. Indeed, it was Cooler and feeling so powerful after slaying the mighty Super Saiyan, he was going to finally put his pathetic excuse of a brother down once and for all.
Quickly powering up to his final form, his brother reached him finally, looking positively peeved.
"My thanks for giving me time to transform brother. I shall make your death swift for that."
"Oh I doubt that. Let me show you exactly why you will be the one dying today." His brother suddenly began to change, growing, his power radiating. Frieza didn't waste a second in firing a blast into his brother's head, full power. The beam cut through and his brother stopped his transformation and simply floated away from Frieza, caught completely off guard and killed instantly.
"Like I said, a swift death. Hm.. this is concerning however. Perhaps it may be worth my time to train, even a little bit? That way I can secure my place as galactic ruler for much longer. If that transformation was going to make my brother as strong as me, imagine what it could do for my own power! I may be strong enough to be rid of daddy dearest.. I will rule the entire GALAXY!" In a massive display of power Frieza laughed through space, none yet living to stand against him.
Though a ship that had narrowly escaped the destruction of the planet was headed far from Frieza. All other escape pods had been destroyed by PTO forces before they were all killed by Frieza in the destruction of the planet. The child in the pod, Kakarot, would grow to become strong, but it matters not. For once Frieza began to train his power exploded in a way he never thought possible. He became so hungry for power in secret he searched for a way to become immortal, for even though his race outlived most others and could survive almost any situation or environment, the part of living forever was not yet possible. So after years of searching he discovered something purely on coincidence, his chimp pet Vegeta had gone to earth after one of his men, Raditz had been killed. Little did he know that Frieza listened in on the scouter communications and Frieza learned of something called Dragon Balls. He had heard of such things before, rumors, about such magical things from a planet called Namek. Taking the Ginyu Force with him, they searched the planet quickly because Ginyu switched bodies with a Namekian. He seemed to like his new body and tricked several of the Namekians to fusing with him after he saw it used to try and defeat one of his men. Quickly his power surpassed his previous bodies, and he became even more loyal to Frieza. Though he was unable to convince the Grand Elder or Nail to fuse with him or grant the wish, Frieza gathered them all up and at first considered threatening the destruction of the planet, but realized that wasn't worth it. They would rather die than grant his wish. Instead he asked if they were re-usable. They were, and they had three wishes. Hearing this Frieza actually knelt before the grand elder, and asked for one of the wishes. One to give him immortality, the other two could be used to restore the lives of the Namekians lost and any damage to the planet. The Grand Elder could feel the truth of Frieza's words, even though they pained the ruler to say. Thus, Frieza was granted his wish. He had attained Immortality, and Frieza and his elite fighting force left the planet peacefully. The Namekians lives were restored, excluding those that Ginyu tricked to fuse with him. The Namekian he had switched bodies, in his grief at being stuck in this form killed himself so that he could join his kind in the other world in his own form. Vegeta however arrived on the planet soon enough. This time Gohan and Krillin were forced to fight him with the Namekians aid, and they were able to defeat and kill him. Goku arrived a few weeks later to find that his son and best friend were living peacefully on the planet waiting so they could bring their friends back to life. Eventually they did and Piccolo decided to stay on the planet for a while and would make his way back one day. The Z-Warriors made their way back to earth where they enjoyed peace for several years…. Until of course the androids struck. Kami, not wanting the dragon Balls to be destroyed again fled to other world. Piccolo was on Planet Namek, Goku fell to the heart Virus because in this timeline Trunks was never born to go back and give it to him. Gohan was able to survive and grew up for several years.
Far far away in space the now Immortal Frieza was enjoying his eternal life, his first action after returning was killing his father in a huge battle that destroyed an entire galaxy, with dozens of planets. Frieza revealed a golden form of amazing power that overwhelmed his father. He quickly became worshiped less as a dictator and more as a god. Several planets that had any chance of resisting King Cold fell into Frieza's new empire.