And the verb, I found out from your link, is hagride
The American Heritage® Dictionary of the English Language: Fourth Edition. 2000.
TRANSITIVE VERB: Inflected forms: hag·rode, hag·rid·den, hag·rid·ing, hag·rides
To torment or harass, especially with worry or dread: “a man hagridden by the future—haunted by visions of an imminent heaven or hell upon earth” (C.S. Lewis).
The American Heritage® Dictionary of the English Language, Fourth Edition. Copyright © 2000 by Houghton Mifflin Company. Published by the Houghton Mifflin Company. All rights reserved.
Given this info, Hagrid does not seem to be a fitting name for this gentle giant