Final answer:
Mike Groom is an Australian mountaineer and guide on the Everest expedition, portrayed as a competent and professional climber by Jon Krakauer.
Step-by-step explanation:
Mike Groom is an Australian mountaineer and one of the guides on the Everest expedition described by Jon Krakauer. In Krakauer's account, Mike Groom is mentioned as a seasoned and respected climber. While the book doesn't delve deeply into his character, Groom is presented as competent and professional in his role on Everest, which is crucial in the high-risk environment of high-altitude mountaineering.