MTL - Last Building on Earth - Chapter 15 confusion

Meet Baek Ri-hyun, the renowned legendary martial artist of murim and was given the title Martial God.In a battle against the Heavenly Demon who has transcended mortality, Baek Ri-hyun was suddenly pulled by an unknown forces to bring him to another world by the power of a goddess who is in need of help from different people, not knowing she pulled a god into her world.Blessed with a system to aid the growth of the future heroes, I don't think he'll need something like it as he ventures the new world.

Memories shape who we are—they define us, anchoring us to our pasts. They are like videos, playing endlessly in our minds.But everything changed one day when people began to relive their memories. However, it wasn’t the pleasant ones that resurfaced. Instead, they were forced to experience their worst moments—or even memories that weren’t their own.Those who managed to survive this haunting experience found themselves watched by strange creatures, and in turn, were granted their powers.As if the world weren’t already thrown into chaos, these same bizarre monsters began to manifest on Earth, threatening humanity with the very real prospect of extinction.Amidst this upheaval, a small, seemingly insignificant beast was born. But it quickly rose to power, only to be betrayed and killed in a cruel twist of fate. Or so it seemed—because somehow, the beast found itself reborn in the body of a human.

This is a story that follows the courtship between a stone from Hell and a god from Heaven that begins in the underworld and spans for three lifetimes in the mortal realm.

“How did you board the Astral Express, walk the Path of the Stars?”“Because I ended the Honkai, altered everyone's fate.”“So your first step on this path was becoming a hero?”“No, it was for survival, searching for a thigh to cling to.”“And then?”Ryan adjusted his glasses, his voice resounding.“I became the thigh.”