Hercules

"You were overconfident"

- Hercules to Pluto

Hercules is a Greek gladiator robot that is shown to be one of the world's strongest robots. He prides himself on his bravery (despite having been destroyed in all of the series he was featured) and courage, which Tezuka thought is a quality various Greeks have.

Hercules is the reigning champion of the Robot Gladiator League, shown when he single-handedly defeating all the other robots that appear on screen, making him well known. This has eventually developed to a point where the crowd would often go knowing he will win (with him seemingly having not losing a battle before until Pluto's arrival).

Hercules' weapon of choice is a arm cannon (similar to Astro and Atlas') that can launch a catastrophic wind at any given time. In his other hand is a battle shield.

2003 series
In the 2003 series, Hercules was given a complete character redesign (along with all the other robots, including Epsilon) that made him more agile and "bird-like", as well as removing his original chariot, as well as his original red armour (which was swapped for a Golden one).

The Rise of Pluto and The Fall of Acheron
Main Article: Pluto-Hercules Battle

Hercules was one of the robots Pluto challenged to a fight. A natural fighter, he responded quite enthusastically, calling out to Pluto to fight him during his matches in the gladitorial arena. He was defeated soon after though, despite gaining the upper hand at the start of the battle.

Robotonia
In the Robotonia episode, he was given a cameo (showing that he has been rebuilt following his destruction) and was fighting alongside Astro in the Robotonia battle.