Thanatos

The Arrival
Not long after Geyser sealed off the throne of the Multiverse Thanatos had returned only to find that his prized possession was now at the heart of a Super Massive Black Hole. Now he longs to find the one who had enough power to thwart his plans. Searching Universe 7 for Geyser turned out to be a chore, but after digging for information out of nearby alien races their legends pointed towards Earth. When receiving false information he would annihilate the entire race and would only spare them if their hints proved true, in this sense you could say he had some sense decency however Thanatos would have destroyed them without hesitation just for looking at him funny.

Thanatos would eventually stumble upon the Heruleans who happened to be at war with Earth at the time. Allying with the god they pointed him in the right direction to find Geyser, hoping that he would destroy the Earth with ease.

God Realm
Thanatos fought Geyser and Nikad at the God Realm, holding them off easily under 20% of his power. Though his original target was Geyser, Nikad proved to be much more interesting at the time; seeing as there was no other Saiyan in history he was aware of that could surpass his strength. This would be the first fight Thanatos would lose in his entire life. He was knocked by an attack so powerful out of the God Realm and into Herulean controlled space. Thanatos armor, before being disintegrated from the energy wave, sent all of its data collected on the two Saiyans to his ship. At that moment his Gen 2 armor was being constructed that would again give him the superior edge in battle.

Ultimate Attacks:
Galactic Buster

A giant energy sphere with the power to destroy an entire Galaxy regardless of its size.

Extermination Wave

An explosive wave fired from his palm with the power to easily wipe out an entire solar system.

Super Attacks:
Death Beam

The same Death Beam used by Frieza, Thanatos can fire it from all ten of his fingers at once.

Multi-Warp/Sphere Barrage

He can warp in and out of reality at amazing speeds to cut the distances between targets from kilometers to mere centimeters. Commonly  when exiting the warp, if he is not using it to maneuver, he will engage in a lightning flurry of punches combined with death ki spheres.

Transformations
Super Saiyan 

Super Saiyan 2