All 12 episodes, as well as the six OVA episodes, from the Japanese anime based on Yusuke Murata's manga remake of the web comic by ONE. Having gone through a rigorous training programme for three years, which resulted in the loss of his hair, the unassuming Saitama (voice of Makoto Furukawa) has become the ultimate superhero, capable of defeating his opponents with a single blow. However, Saitama has become jaded by the lack of effort needed to defeat his foes and performs his heroic duties with little vitality.

A young cyborg named Genos (Kaito Ishikawa) approaches Saitama looking for guidance in how to become stronger and when Saitama agrees to mentor him the pair embark on a quest to fight for justice. 

The episodes are: 'The Strongest Man', 'The Lone Cyborg', 'The Obsessive Scientist', 'The Modern Ninja', 'The Ultimate Master', 'The Terrifying City', 'The Ultimate Disciple', 'The Deep Sea King', 'Unyielding Justice', 'Unparalleled Peril', 'The Dominator of the Universe' and 'The Strongest Hero'. The OVA episodes are: 'The Shadow That Snuck Up Too Close', 'The Pupil Who Is an Extremely Poor Talker', 'The Ninja Who Is Too Complicated', 'Bang, Who Is Too Overbearing', 'The Sisters Who Have Too Many Things Happening' and 'The Murder Case That Is Too Impossible'.