Training is usually associated with pokemon in captivity, but it is actually more common than not for fighting pokemon to practice independently. Kubfu in particular take this tendency to an extreme level, rejecting trainers as superfluous for most of their lives, or at least demanding far more proof than defeat in battle to be captured; they believe, rightly or wrongly, that they can become far stronger on their own.
An insular variant of Teddiursa, Kubfu have taken on the personalities of the hermits, warrior-monks, and martial artists to call the Isle of Armor home – or perhaps it is the other way around. Rather than valuing strength as a means to kill prey or protect themselves, these pokemon appear to value it for its own sake, training hard even when food is abundant and they are in no danger whatsoever. Kubfu perform feats of strength around the island, from pulling up Alolan Diglett to climbing the cliffs outside Challenge Road. They challenge their fellow fighting pokemon to successive bouts until they finally faint – an outcome the Kubfu put off as long as possible, but one which is inevitable, for no pokemon can fight forever.
Kubfu's full potential does not depend on the aid of a trainer, but on the mastery of a fighting style they do not naturally learn, and that few humans on Earth even know. When Kubfu finally seek trainers, it is not because they need the help of living human beings to become stronger, but because evolution to Urshifu depends on techniques passed down by the old masters, and Kubfu wish to do their part to grant their successors an easier path to evolution. It is easy enough to open the ancient scrolls, but one could hardly write them with a bear's paws!