Narth, the old Lord Harth, was burnt by changer blood when Gerridon's forces attacked East Kenshold. He was eaten away by it slowly and died of it. After he died, his son became Lord Narth, and tried to ride Nathwyr, his father's old Whinno-hir, without it's consent. The six older yondri objected, and the young Lord Harth threw them out.
↑Dark of the Moon, "Appendix I: The High Council" — "Minor houses such as the Harth of East Kenshold and the Min-drear of the High Keep are located near the Barrier and help to maintain it."
↑God Stalk, Book II: Crown of Nights, "Chapter 8: Voices of the Past" — " 'Then one night the riders came down on us from the north, yes, out of the Haunted Lands. […] He was a brave old man and stood with us shield to shield all that long night. Their blood was his undoing. […] The horrible thing was that he lived nearly two years after that, the flesh slowly crumbling away from his living bones. When he finally died, his son told us yondri that we no longer had a place there. Six of us started out for Tai-tastigon.' "
↑Dark of the Moon, "Chapter 3: Old Friends, Old Enemies" — " 'That's probably young Lord Harth, trying to ride Nathwyr again,' said Marc bleakly. 'Nath was old Narth's mount, a full-blooded Whinno-hir. We older yondri tried to tell the boy that no Whinno-hir can be ridden without its full consent, but he wouldn't listen. We insisted, and he ordered us to leave.' "