Hard to say exactly. Sometimes it's a collaboration between multiple creative talents in the manga industry. Their combined efforts bring chapters like this to life, but pinpointing one individual creator can be tricky.
It could be a team of translators or a publishing company specializing in manga translations. But the exact entity might vary depending on the region and licensing.
I think it's the work of a team of manga artists and writers, but I don't have the specific names. You might find the info on popular manga review sites.
I'm not sure exactly who made it. But usually, mangaka get inspiration from various sources like their own imagination, popular culture, or personal experiences.