Teihiihan

The Teihiihan (also known as Cannibal Dwarves) are figures in Native American folklore, specifically from the Arapaho, Gros Venture and Cheyenne Nations : who were believed to engage in battle against these fearsome creatures in ancient times and thus they have become common antagonists in tales of cultural heroes and similar.

History
The Teihiihan were said to be vicious creatures that fought against several Native American tribes and had a  habit of devouring enemies - they were roughly the equivelant of trolls or goblins in other cultures.

One story of these creatures concerned a warrior who was captured by a Teihiihan and tried to dely his demise by striking up a conversation with the monster, noticing several small hearts hanging on the walls near him and he thus asked the creature the purpose of the organs.

The Teihiihan were not very intelligent creatures and thus the monster explained simply that the hearts were those of his relatives, who were out hunting and thus the hunter began piercing each heart - which killed off the monster's relative from afar but the creature was too stupid to react.

Thus the warrior ultimately pierced the last remaining heart, which killed his captive and allowed him to escape.

Appearance
The Teihiihan were said to be child-sized, bloodthirsty humanoids not dissimilar to goblin or trolls, thus were often ugly and not-too-smart - despite their small size they had a variety of powers that made them feared even by experienced warriors and braves.

Abilities
The Teihiihan were said to be extremely strong and able to outrun warriors despite their small size, they were hunters and thus could use basic tools and weapons - they were also magical in nature and some stories had them storing their hearts in caves, making them invulnerable to harm unless the hearts were pierced.

For all their powers however they were also extremely stupid creatures and thus easily tricked or defeated by those with quick wit or clever minds.

Trivia

 * Teihiihan follow a very strong and recurring theme in Native American folklore that cannibalism will turn people into monsters, other examples of this are the Wendigo and the Kanontsistonties.