William Rolfson (Earth-616)

Origin
William Rolfson is the son of Autumn Rolfson and Apocalypse. In her time as a Horsemen, Autumn ended up having an affair with Apocalypse. Scared that Apocalypse would kill him if seen as a threat, Autumn went into hiding to raise William. When William's Mutant powers arouse, he was granted immense power, but was forced to wear a containment suit.

Dark Angel Saga
Autumn continued to raise William until they were found by Archangel, who came to be Apocalypse's replacement at the time. He recruited Genocide to cleanse the world and recreate it in his ideal image. When Autumn learnt of this, she attacked her former Horseman, but was killed by Archangel.

Apocalypse Twins
Taking his father's place as the new Caretaker of Earth, Genocide, along with his own Horsemen, travelled to Starcore Station to broadcast a message to the gods (Celestials) his father served.

As the Celestial that was summoned arrived to give Genocide the Death Seed, the Apocalypse Twins arrived and attacked. As Uriel attacked the Celestial with Thor's enchanted axe, Jarnbjorn, Eimin saved their mother, Ichisumi, and killed Genocide's Horsemen. Uriel confronted Genocide after killing the Celestial. Genocide however survived his encounter with the Twins and returned to Earth.

Apocalypse Wars
Trying to purge Earth of the weak, Genocide convinced Warren Worthington III that Clan Akkaba would prevent him becoming Apocalypse again by removing his wings. Using Warren's wings, Clan Akkaba created an army of Archangel clones called Death-Flight.

Genocide was later confronted by Magneto and Psylocke, who had discovered his secret base in Green Ridge by the Archangel Clone on Magneto's X-Men team. They ere however defeated. When Magneto and Mystique discovered his plans and attempted to foil them by killing Warren, Genocide felt his Death-Flight awaken as the result of Psylocke summoning Archangel, their leader, after she broke from her cell. In a gruelling battle against Magneto, Genocide was killed and his Death-Flight ceased.

Powers
Bio-Furnace Energies: Genocide could generate radioactive plasma, which he often used in combat situations. At his peak, he could generate bioplasma blasts reaching a temperature equal to the core of the sun.

Equipment
Armoured Exo-Shell: Genocide relies upon an exoskeleton / containment suit to keep his devastating bio-energies under control. The raw energy his body produces will explode outwards if his armour is breached. The suit increases Genocide's physical strength and is highly resistant to damage or penetration. It also provides an arm-cannon for channelling his radioactive plasma into directional blasts.

Facts

 * Genocide would just be over the age of 15.
 * Considering his mother would have been around the New Mutants age range when she debuted in X-Force #12, Clan Akkaba and Dark Beast had to use age acceleration technology (Nate Grey was accelerated from teen to adult by Mister Sinister), assuming she gave natural birth.
 * Genocide is very similar to DC's Blight as of powers and design features, such as their bodies and containment suit designs.