Well, Link isn't easily intimidated. Or particularly used to Vader's vein of intimidating, really. The scarce few people in Hyrule who Link considered intimidating had a very, very different vibe.

"That's a lot," Link says. It certainly sounded like an impressed amount of stuff, even if Link wasn't exactly able to follow along with all of it. (What was glucose, and what was it doing in the man's blood?) "Did a Great Fairy upgrade it?"

Luke hadn't heard of Great Fairies. But who knows - maybe this man had.