Dragon Ball: Goku Rebirth

King Cold and Cooler had arrived on Earth, this time to attain vengeance for Frieza. You see they were shocked to hear a Namekian could defeat Frieza and to further weird them out was that it wasn't Slug it was someone else.

King Cold was quite complacent as he believed it was just a one-time thing and that Frieza was too careless and fell for the Namekians magical tricks, 'Yes, that's it Frieza fell for one of those punks tricks, there's no way he could have lost other than a trick'.

...

Abysmally a strange spacecraft had appeared in front of Goku and co, they all saw the boy he looked exactly like Goku but with blue hair, you see there was only Cold and Cooler left as the Z-Fighters had already cleared the underlings.

The blue haired boy did not talk to them rather he rushed to Cold and brought out the Tapion Sword and slashed at Cold. "SWOOSH!!" "WHOOSH" he sent out two sword strikes and cross-hatched them the attack cut Cold quite a bit and he coughed up blood, Cooler was on the side just watching with amusement.

Cold looked at the boy and said, "You who are you, you are no Namekian rather a Saiyan I can see your tail and your gravity-defying hair, it seems that I was right no Namekian could possibly defeat my son, you must be the Fabled Saiyan of legend, The Super Saiyan"

Cold then continued, "Even if you are a Super Saiyan you will not be able to defeat me, Boy!!

And that Sword of yours, if I'm not mistaken, is made of Yami No Katchin the strongest Metal Alloy in the universe, Katchin infused with the darkness attribute huh