Karasu Tengus are described to be creatures with bird heads and wings and the body of the human form. A majority of the Karasu Tengus in existence have the appearance of blackbirds, while some take the forms of other birds. They often carry either ring-tipped staffs or swords to use for defense.

Karasu Tengus have interesting abilities. They are known to harness all the powers of nature. They are capable of teleporting from one place to another in the blink of an eye. Some have even been known to shapeshift and take the forms or other creatures, much like the Kitsune. They communicate telepathically and never open their beaks. Karasu Tengus can choose worthy people to become Ko Tengus, or "little Tengus."

Karasu Tengus are very arrogant and quite volatile. They have been known to play tricks on other people such as starting fires, stealing children, and relocating disoriented people in rather odd places. Karasu Tengus are hatched from large eggs and live in the mountaintops. They are very protective of their territory and threaten to kill any and all intruders who dare enter. They are masters of the sword, and it has been told in lore that they were the originators of the samurai and the ninja. Of all the Tengus in existence, the Karasu Tengu is of the highest rank of importance and power.