He is one of the five Gods (six Gods, according to the third "alternative writing" of Nihonshoki (Chronicles of Japan)) created by Susano from the Yasaka-no-magatama Bead which he had gotten from its original owner Amaterasu Omikami (the Sun Goddess) in the Chapter of Amaterasu's and Susano's covenant. Kumanokusubi was declared Amaterasu Omikami's offspring because he was born from her possession. He is referred to as Kumanokusubi no mikoto in Kojiki (The Records of Ancient Matters), while Nihonshoki calls him Kumanokusuhi in the main text, Kumanooshihomi in the first "alternative writing," Kumanokusuhi in the second "alternative writing," Kumanooshihomi or Kumanooshikuma in the third "alternative writing," and Kumano okuma in the third "alternative writing" of the alternative chapter (the Chapter of Iwato gakure, the hiding of Amaterasu Omikami in the heavenly rock cave). In any of those descriptions, he was alleged to be the last (fifth or sixth) born god.
Probably 'Kusubi' (or Kusuhi) in his name means 'the mysterious divine spirit' or 'mysterious fire.'
Kumano is a place-name, indicating either Kumano Taisha Shrine in Izumo (Matsue City, Shimane Prefecture) or Kumano Sanzan (three major shrines of Kumano) in Kii. The present enshrined deity of Kumano Taisha Shrine is 'Kumano okami Kushimikenu no mikoto,' but some people insist that originally Kumanokusubi was enshrined there. The enshrined deity of Kumano-Nachi-Taisha Shrine (Nachikatsuura-cho, Higashimuro-gun, Wakayama Prefecture), one of the major shrines called Kumano Sanzan, is Kumanofusumi no okami, who is generally supposed to be Izanami but alleged to be Kumanokusubi by some people.