[No System] + [Decisive and Ruthless] + [Martial Soul Upgrades] + [Long Story with a Measured Pace] + [Smart, Logical Characters]
(50 chapters of keeping a low profile and developing, 50 chapters of invincibility across the whole school, 200 chapters of invincibility on Blue Star, 1,000 chapters of invincibility across the world.)
In this high-martial world, humanity has ventured into space, only to face invasions by alien races and the threat of spatial rifts.
On the eve of his final year of high school, Sun Zhan awakens an F-rank useless martial soul: a monkey.
From then on, a genius becomes a failure. In this high-martial world, without a powerful martial soul and combat strength, you are nothing.
But Sun Zhan unexpectedly awakens a divine ability that purifies bloodlines. As long as he keeps absorbing energy, his martial soul can evolve without limit.
That so-called useless monkey turns out to be a legendary being capable of destroying heaven and earth.
From then on, Sun Zhan wields a divine staff, killing any god or Buddha who stands in his way.
He fights until no one among humanity on Blue Star dares look down on him, until no one under heaven dares claim supremacy.
While his peers are still sweating it out at martial arts universities, Sun Zhan has already charged into the universe, forcing the alien races to bow and submit.
“What? Sun Zhan awakened a useless martial soul?!”
“What? Sun Zhan is holding a long staff and crushing all the prodigies in the province?!”
“What? Sun Zhan became the top scorer on the college entrance exam?!”
“What? We just finished university, and you're telling me Sun Zhan has fought his way through the universe?!”
(The pace is a little slower at first, mainly to lay the groundwork for a long story without a System. The pace picks up after the college entrance exam.)
P.S. Don't let the chapters pile up. Try to keep up with updates, or the story may get abandoned.
P.S. 2: The introduction is correct: he becomes invincible while keeping a low profile and steadily developing.
What does it mean to have brains and logic? The opening of Iodine in Good Code.