The Jotunn Technique, also known as the Jotunn Mode, is a means of reaching a specific form, which greatly enhances your strength and maneuverability, as well as granting users several powers, similar to Sage Mode.
It is achieved by creating complete chakral independence. This means that, instead of relying on your central body to produce chakra for your 360 tenketsu, you force these chakra points to become independent by stopping the chakra flow, and creating an environment in which the chakra must be produced by the tenketsu individually. This is done by a very specific technique, the first initiation of which involves a Hyuga blocking off a number of the prospective user's tenketsu, to better facilitate training of chakra contorl and diversion of chakra to different tenketsu. This first step is known as primary training, and is as much about gaining chakra control as it is about beginning the technique. After primary training, the user can do this alone through advanced chakra control. After gaining better chakra control, the user must begin the second step of training, which involves pressing the edges of each Tenketsu's boundaries, so that the used chakra from multiple tenketsu mix at these borders, where it can be used as a "fence" to block off other Tenketsu. The moxing of chakra away from the center also causes the tenketsu to harden, blocking off the flow to the rest of the chakra system. The third and final step of training is to practice the second step repeatedly, for longer durations each time, to pressure the tenketsu into improving their chakra levels. The final step is to utilize all of these steps together and complete the separation, entering the Jotunn state and increasing its effects tenfold. The process can kill most who attempt to use it, but if one manages to form the chakra enough to gain even the smallest of control, if they are practiced users, they can use that to start the process. A practiced master of this technique can produce many times as much chakra as a normal ninja of the same level, rivaling, in this form, even users of the fabled Sage Mode.
While in this form, users’ bodies take on a rugged, grizzled look, due to the nature of the separation of the tenketsu. Their skin becomes rougher and darker, and their joints gnarled, and they gain a slightly hulking, more powerful appearance. At a higher level, they can appear to become covered in a blackish armor of stone or gem, and their form twists to become hulking and beast-like. When the form has been reached, the chakra forming in the tenketsu forces the body to bulge outward, creating an icy and dark chakra around them, and the Tenketsu Devourer chakra can branch out in spikes. Their most distinguishing feature, however, is that a crescent of ice forms underneath their eyes, and a spike of ice juts out above them. When Nurarihyon Ayakashi uses this technique, his toughened black hide extends to form two bull-like horns and a beast-like head around his own.
In this form, a user gains great strength, becoming physically powerful even for their enhanced size, and able to crush boulders with ease. All physical traits are enhanced, and the user can warp their form to a personalized state which allows them to utilize this advantage more proficiently. They also have enhanced chakra, due to the tenketsu producing larger amounts of chakra overall when forced to operate solitarily. This causes their jutsu to increase in power, and their chakra reserves to deplete more slowly. They are also seen to shrug off what would otherwise be debilitating injuries, as they are less harmed by massive wounds than normal ninja. They can also utilize the Jotunn Mode for several techniques that can only be utilized while in this form.
Because the tenketsu become separated, the chakra system cannot be used, so if one tenketsu ceases to produce its own chakra, or is depleted of its supply entirely, then that chakra point may be permanently damaged, and the body will stop using the Jotunn Technique in order to reopen the chakra circulatory system and attempt to replenish the tenketsu’s chakra. Also, while the user's body is extremely strengthened in this form, if a force is strong enough to crack the form, it can destroy the mode, dispelling the technique and severely damaging the user.
In this form, water style Ninjutsu work especially well against the user, doing more than average damage. If the Jotunn Technique’s user is less skilled than the user of the water technique, the water chakra can wash away the barriers around the tenketsu, ending the jutsu and depleting the chakra supply greatly.