Denathrius has the bent legs and hoof-shaped feet of a Nathrezim, as well as their ears and horns, but is completely lacking their usual wings. He also looks remarkably different from usual Dreadlords in a few other ways despite being connected to them through hidden lore tidbits.
If he's an "uncorrupted Nathrezim" then why does he have hooves and horns?
And no, he's not a Venthyr, because those are the creatures he created in his image. They lack his feet and horns.