The Kekkei Genkai itself was originated from a mutated gene inside of a random person. The mutated gene allowed the user to create what is now known as Reikiton, the element of "Cold," but disallows them to use any form of Katon based jutsu. All jutsu that are in fact Katon element will instead come out as a Reikiton element technique. (For the purpose of power scaling I'll convert Katon jutsu into Reikition jutsu. It works in the same sense that Raiton or Katon work; as a basic energy. This energy is able to create an inverse effect of Katon and freeze whatever it touches rather than burn it. Much like how fire can burn, melt and heat up matter, Reiktion is able to chill, freeze, and cool matter. Reikiton techniques themselves look almost identical to Katon techniques except for only one visible difference. The flame is a white and gray color instead of a yellow and red. Otherwise the target would have no idea that the attack would actually freeze their skin instead of burn them upon contact. Although, because burning and freezing give of nearly the exact same pain signals, the target may not even know that they are being chilled until they notice the air crystallizing around them due to the cold freezing the water vapors.

Once a member of the clan learns how to use Reikiton in its original state, they can learn a secondary form of the technique which works more like what Katon would, but only in theory. These techniques are only A rank and above due to their deadly nature, and affect organic matter amongst others. If these refined flames come into contact with combustible material such as Carbon or Hydrogen (Must be solid or liquid), they will burn like a normal fire, but with the obvious gray and white glow as opposed to yellow and red. The flames will remain on the surface of said object until water or any non-combustible material puts the flames out or the combustible substance depletes, much like a normal fire. The only difference between this fire and a normal fire is that it gives off "cold" energy, or reduced heat energy instead of blazing hot energy. This makes it so that anything around the flame also begins to freeze and 'catch on fire' just like a normal flame would except inverted. The reason for the deadliness of this attack and for its high rank is because it could potentially freeze a forest and kill an organism from lack of heat. It is also much more effective than normal fire in killing organic matter, as organic matter is more prone to lack of heat than too much heat. All techniques baring this power are labeled "Elite" to signify this exact ability.

Should this technique come in contact with a Katon attack of equal rank power, it would have the same effect as a negative charge pressing a positive charge, or an anti-matter piece pressing against a normal matter piece (of course, far less destructive). The collision itself would create a rather large explosion, canceling out the Katon and Reikiton abilities entirely. The explosion would not produce any heat, but rather create a shock wave capable of pushing a truck off the ground (if in direct range of the explosion) from the sheer force. The power of the explosion varies between attack rank, with the truck moving shock wave being A rank. If the rank difference between Katon and Reikiton is 1 rank placement or more, the stronger element overwhelms the other element and reduces the winning element's power to whatever the difference is. The rulings are as follows:

(Assuming the higher rank is the winner)
D + C, C + B, B + A, or A + S = D rank power outcome.
D + B, C + A, or B + S = C rank power outcome.
D + A, or C + S = B rank power outcome.
D + S = A rank power outcome.

Note: The power outcome basically means that the strength of the winning attack will become X rank after defeating the lower rank. So if someone used a C rank Katon jutsu against a B rank Reikiton jutsu, the Reikiton jutsu would win, but the power would be reduced to that of a D rank Reikiton jutsu.

Reikiton has several weaknesses, but also several strengths. Different elements react with it differently, and therefore does not share the same properties as Katon, which is weak to water and strong against wind. The list below will explain the relationship with Reikiton and the other five elements.

Katon & Reikiton
When struck with Katon different effects are present. If equal in rank, both are nulled and a pure shock wave explosion occurs. If one his stronger; that element wins but gets severely reduced in power. (View Kekkei Genkai section for greater details)

Suiton & Reikiton
Unlike Katon, which is weak to Suiton, Reikiton shares a different relationship. The Reikiton cools the water, and with high enough rank, can potentially freeze it. If the water is in constant motion though, this does not occur and the two elements practically ignore each other. In the case that the Suiton is being wield by chakra the stronger jutsu naturally wins and no one element has an advantage over the other.

Doton & Reikiton
Earth is a great weakness of Reikiton. If the element of Reikiton attacks Doton elements, it will be extremely weak to it. Doton itself cannot burn nor can it be altered by the cold energy of Reikiton; therefore using a basic Reikiton attack on Doton is entirely ineffective. If the Reikiton technique is stronger than the Doton technique to the same extent as a Katon would be to Suiton; then Reikiton can break through the Doton with the sheer force, but would lose all cold properties after breaking through.

Fuuton & Reikiton
Reikiton is fairly strong toward Fuuton, but to an extent. If the Fuuton attack is of lower rank than Reikiton, Reikiton will feed off the Fuuton element and grow larger. If the same rank: the elements will react to each other normally with no added effects. If Fuuton is of higher rank than Reikiton, then the Fuuton will naturally blow out the Reikiton flames.

Raiton & Reikiton
This relationship is rather odd compared to the others. If a Reikiton technique and a Raiton technique were to collide, neither would be directly affected by one another. The main reason is because Raiton is usually too fast and can zip right through the Reikiton attacks should they not have enough solidity to them. Indirectly though, Reikiton and Raiton are both weakened when they collide. Both will go through one another, but the cold powers of a Reikiton technique will lower and the electrical powers of a Raiton technique will be reduced. The main reason for this is because Raiton is generally a whole bunch of electrons/electric energy. Because Reikiton is cold it naturally slows down electrons and thus makes the stunning effects of Raiton weaker. But also; because Raiton is free energy it warms up the Reikiton attacks and makes them less cold. The power of both Raiton and Reikiton are unaffected, but the passive ability is reduced depending on rank. If equal rank both Raiton and Reikiton lose half their passive abilities. If one is stronger, the weaker loses 65% and the stronger loses 35% of its passive ability. Note: The Raiton and Reikiton techniques have to directly collide. This is very difficult to achieve considering Raiton is quick and Reikiton is mediocre in speed. Upon collision, the two do not weaken in firepower. Therefore if an attack like chidori hit a Reikiton attack of similar ability the attacks would still do their damage; just do less stunning/cooling. If one of the elements is 2 ranks above the other the stronger element will eliminate the weaker by strength alone.

Code:

[b]Name:[/b] [Reikiton] Endan - [Cold Wave Release] Fireball
[b]Rank:[/b] C
[b]Type:[/b] Ninjutsu
[b]Range:[/b] Close~Mid
[b]Element:[/b] Reikiton
[b]Description:[/b] After performing the necessary hand seals, the user proceeds to inhale a large sum of air, before expelling it with their mouth, causing a blue fireball to extend and fire at the target. Capable of causing minor freezes and can cool the air rather effectively.
[b]Chakra Cost:[/b] 5

Code:

[b]Name:[/b] [Reikiton] Dai Endan - [Cold Wave Release] Great Fireball
[b]Rank:[/b] B
[b]Type:[/b] Ninjutsu
[b]Range:[/b] Mid-Long
[b]Element:[/b] Reikiton
[b]Description:[/b] After performing the necessary hand seals, the user proceeds to inhale a large sum of air, before expelling all of it from their mouth, creating an enormous, white fireball capable of freezing most things in its path. Can cause frostbite if the target is trapped inside it for too long. Can also explode if the user adds too much chakra, causing the cold energy to flood the location.
[b]Chakra Cost:[/b] 12

Code:

[b]Name:[/b] [Reikiton] Hibashiri - [Cold Wave Release] Running Fire
[b]Rank:[/b] B
[b]Type:[/b] Ninjutsu
[b]Range:[/b] Close~Mid
[b]Element:[/b] Reikiton
[b]Description:[/b] After performing the necessary hand seals, the user stamps their foot on the ground, casing a surge of fire to run from the tip of their toes and along whatever path the user wishes to home in on the target. The fire has a bit of a cutting potential, and is made of Reikiton, allowing it to freeze and cool whatever it touches much like how fire can burn and heat whatever it touches.
[b]Chakra Cost:[/b] 12

Code:

[b]Name:[/b] [Reiktion] Seiei • Atsukurushiisen - [Cold Wave Release] Elite • Sweltering Beam
[b]Rank:[/b] A
[b]Type:[/b] Ninjutsu
[b]Range:[/b] Close~Long
[b]Element:[/b] Reikiton
[b]Description:[/b] After performing the necessary hand seals, the user coats their hand in Reikiton chakra before ejecting a powerful white beam of extremely cold fire from their index and middle fingers. The beam, at close range (1 foot max), could shoot through a person, but at mid range or more will simply freeze-burn them severely. The flames actually "burn", but instead of creating chemical reactions, they absorb the bonds in matter to feed the fire. Cannot burn gases and requires either a seal or large exertion of chakra to end the flames.
[b]Chakra Cost:[/b] 25