If there's any kind of threat in or around Death Mountain, wouldn't Argon already be aware of it? Hell, he had to climb down from Death Mountain so logically he could have seen or even encountered whatever the danger was if only briefly.
Not exactly, Death Mountain Range in this Hyrule, Death Mountain is the largest in a range of mountains named after it.
I feel I should note that we were going to have a map, but there were complications and we didn't. Just ask me (or the characters) about any geography questions.