Sooner or later Laura the Saber Of Blood created a Zerg creature that nearly perfectly took her occupation among her Brood in case she'd be absent. And it was thanks to genetic material from her own pure-hearted sister, hence the infested clone, not an original.

Since Broodmother Naktul was occupying desert environment it wouldn't be any surprise that Naktul Brood would become a part of the Rubybrood. Once upon a time Naktul's own body even evolved, after consuming a human genetic material, under influence of ancient artifact that later went missing and most probably was never seen again. Like Zagara and Niadra, Naktul can switch between forms of course.

(Naktul and Infested Terran belongs to Blizzard)