Saitama's strength in the manga comes from his intense training and unwavering determination. He pushed himself to the limit every day, which eventually led to his overwhelming power.
Not necessarily. The concept of 'the strongest' is relative and depends on various factors. Saitama is definitely a force to be reckoned with, but there could be characters in other stories with equal or greater strength and abilities.
Saitama obtained his power through a rather unconventional way. He simply trained non-stop, doing mundane exercises like push-ups, sit-ups, and running. This extreme dedication transformed him into the powerful being he is now. It's a simple yet unique origin story.
Saitama's speed in the manga is incredibly fast. It's hard to put a specific number on it, but he can cover great distances in no time and react with lightning speed to any threat.
Saitama's strength in the manga is basically off the charts. He has no known limits and can take down any foe with ease. His power seems almost invincible.