After being fired from the diamond squid, I became a sea patrol ranger.

[There is a female lead, but she doesn't join the Starry Sky Train and is only marginally connected to the main storyline.]
Spah travels to the Star Iron world and, by chance, gains the ability to "replay the past," which leads him to join the Interstellar Peace Corporation.
In just a few years, Spa has achieved both fame and fortune, and is only one step away from becoming one of the "Ten Hearts of Stone".
but……
My ambition is to reach the stars and the sea, and to live a life of swift justice and vengeance!
Taking advantage of a tragic incident, Spare submitted his resignation to Diamond. From then on, the debt collector of [Guardian] became the pursuer of [Hunter].
His legend is etched on the bountiful battlefields of hunting. His monument stands tall on the snowy plains of Yalilo.
He is a legend of Punk Lord's rebirth and a permanent honored guest of the Immortal Boat Alliance.
Spare, single-handedly with a gun, made the Antimatter Legion and the Abundant Fel so fearful that they dreaded even in their dreams!
……
Estelle: That's the story of Spa-gege. He's really amazing!
Feixiao: I object! Your description is too conservative. I can't beat Spa at all.
Robin: Spa's skills are really hard to describe... Anyway, I'd like him to be a guest at my concert!
Silver Wolf: I want to play games with Spa...hehehe
[Memory], [Preservation], [Hunting]... Three intertwined destinies lead to the starry river!