The supernova clan is a group of shinobi who posses the latent power which is in every human being called haki. The supernovas are lead by Goku and are spread out in every village around the ninja world. Haki is awakened through extensive training and battles. There are three types of haki.
Armament Haki allows the user to physically manifest his Haki into an invisible armor. This naturally allows Busoshoku Haki to be used for defensive purposes, being able to nullify and withstand attacks that would have otherwise harmed the user. With enough skill and strength, the user can use Busoshoku Haki offensively, imbuing into weapons and some attacks to strengthen them. This naturally also goes for the user's body, using Haki to strengthen his blows. Advanced Haki users can manipulate Haki as they see fit and can harden it into black manifestation, increasing its power even more.
Kenbunshoku Haki allows the user to manifest Haki into a sixth sense, giving them the ability to sense the presence and location of an object, as well as what kind of animal they are and if someone is alive. With enough skill and training, this Haki can have premonition abilities, giving the user a mental picture of what the opponent is about to do, in short, the ability to predict moves.
Haoshoku is even rarer than the other two and cannot be strengthened through training, but only by the strengthening of one's spirit. This means that as a person goes stronger as a person, their Haoshoku grows stronger as well. Very few people awaken Haoshoku Haki and it is usually awakened in moments of dire danger. Haoshoku Haki allows the user to dominate the wills of others, knocking them out.