Help finding short story

I’m a reference librarian trying to help a patron locate a story he remembers from a middle schoo/high school textbook (circa 1975). The details are as follows:

“The short story was a science fiction or fantasy short story in which a scandinavian nobleman (he was Norwegian or Swedish) was the host of the narrator of the story. He had platinum blond hair and pale blue eyes that were slanted. He told the narrator “we came from Central Asia, near China.” Later in the story, the narrator saw a large serpent or dragon swimming in the ocean and it was implied that this was the nobleman who had “shape-shifted” into the serpent. The character was the host of the narrator of the story and the narrator recounted the events his visit.”

I thought from the platinum blond/slanted eye description that the character might be Moorcock’s Elric of Melnibone, but the patron is sure that is not right, and Elric doesn’t match the rest of the qualifications anyway.

Any ideas on what this story might be? The patron also says it was considered a classic short story (as I’d imagine it would have to be to appear in a school textbook in the 70s) and not fast-paced.

Thanks for any help you all can provide!

Not much help, but Strindberg wrote at least one shapeshifter character (Úa in A Dream Play). While this doesn’t sound like that, since he was Scandinavian and it was a “classic” story I wonder if it could be one of his.