That guy is Shanks. Has 1 arm and regular old sword.
That guy casually strolled into middle of war.
The people participating in that war weren't any ordinary people.
We had people that can manipulate magma, light, ice, fire, blackhole, earthquake, sand.
We had people that can transform into diamond, a Phoenix, rubber, and even a Budha. Also we had the best swordman in the world, the master of fishmen karate, a woman who has the power of Medusa, and many more.
And that crazy guy walked into the middle of war and said "This ♥♥♥♥ is done!"
And you know what happened?
"The war really ♥♥♥♥♥♥♥ ended"

Shanks is badass.
Be like Shanks.