After transmigrating to the Honkai world and serving as a captain, Zhou Fangyang completed his journey there. On his way home, his daughter Zhenqi ran away from home. To bring her back, Zhou Fangyang traveled to Teyvat, where he met a goddess who looked a lot like his daughter. To find his daughter's whereabouts, Zhou Fangyang set off on a journey across Teyvat with Ying, whom he had rescued, while also finding his daughter a few new stepmoms~
(Zhenqi's perspective: "Why Do I Have So Many Stepmoms?" Jean's perspective: "How I Accidentally Stole My Sister's Boyfriend" Barbara's perspective: "How My Sister Stole My Boyfriend")
Years later, a strange piece of gossip spread across Teyvat: whenever a Traveler from another world appeared, you had to kill him as soon as he showed up. Otherwise, he would run off with every pretty girl in the world...
(If you've read My Captain Isn't a Tool Anymore, the protagonist should be familiar, right? He's a total lecher.)