The Rampaging Cyborg

No matter what, I cannot die until I have destroyed that rampaging cyborg. To that end, as a cyborg for justice, I must continue to fight evil until I encounter that rampaging cyborg again. I must get stronger!

The Rampaging Cyborg (暴走サイボーグ, BōSō Saibōgu) is the cyborg that destroyed the home town of Genos and murdered his family. Since then it is his archenemy.

Appearance
The Rampaging Cyborg has a brief appearance during a conversation between Drive Knight and Genos. It appears to look like a humanoid robot.

Personality
The Rampaging Cyborg is insane and uncontrolled, having destroyed everything in sight at Genos's town. According to Genos, this is probably because a failed body modification generated an irregularity in its brain.

History
Four years before Genos met Saitama, the Rampaging Cyborg attacked the former's hometown, destroying everything and even murdering his family with Genos being the only known survivor. While tracking down the Rampaging Cyborg, Dr. Kuseno came to the ruined town and found Genos. It's also been known as the Mad cyborg.

Drive Knight claims that the rampaging cyborg destroyed his village too, and that he thus has a similar past to Genos. He did not give a specific time frame. Drive Knight tells Genos that the Rampaging Cyborg is a creation made by Bofoi.

It is also revealed by Dr. Kuseno that the Rampaging Cyborg too killed the scientist's family in one of the villages it went around destroying.

Neo Heroes Uprising Arc
After Drive Knight explains his history about the Rampaging Cyborg to Genos, it is revealed no hero records have been shown to take down the Rampaging Cyborg and it has not shown up for a few years.

It is theorised that it is most likely in sleep mode, hidden away with the rest of Bofoi's robotic creations.

Abilities and Powers
Although the full extent of what the Rampaging Cyborg is capable of is unknown, based on what Genos's mentioned, it can be inferred that this rampaging cyborg is very powerful and dangerous. It was able to completely ruin Genos's town, having destroyed everything there including parks, schools, and buildings.