Clan Kakuriki is an assassin clan that exists in China.
Their members have been shown as bald men with large, muscular bodies wearing robes. They have no eyebrows, speak crudely to all others and are quick to attack all enemies before them. When showing their abilities, throbbing veins show on their faces.
They were hired along with 4 other assassin clans, by Ryo Fui, to kill the Qin King at night. Along with the other clans, they infiltrate the palace and are found by Ka Ryo Ten who accidentally stumbles into the group. One of them grabs her by the neck and is about to finish her off when Kyou Kai appears, asking them to hand Ten over. They tell her that they planned on killing all the competition and will start with her. Two of them use Kakuriki Gouken to attack but miss, hitting only the wall. They tell her that her sword is useless as their Gouken skill makes them impervious to all weapons. Kyou Kai destroys this notion by instantaneously cutting 3 of them in half which angers the remaining men. They attempt to attack her but fail to hit her and are all killed by Kyou Kai.
The clan uses their brute strength and a unique skill called Gouken. It enables them to coat their bodies in a layer of hardened "ki" and can be used to shatter a boulder with a single strike. They say that its defensive capabilites makes them impervious to all sword attacks. As an attack, a punch using Gouken has enough force to leave an indent on a stone wall.
All the hired members are killed by Kyou Kai in the royal palace.
This is the first time the concept of ki is mentioned with regards to combat.