Name: Zann's automail arm
Who owns the weapon: Zann Kyu Ketsuki
Where it was found/Who made it: Zann made it himself after he lost his arm in a battle with Futashi Ryo
The Range of the weapon: 0-100m (From hidden projectiles and weapons)
Weakness: Users of Mikyo's living metal ability, raiton attacks
Description: Zann made this arm after Futashi cut his right arm off in a fight. The material is made from living metal which he attained from Uno Harum, and is 100 times stronger than steel, making it impossible to cut. It is bound to Zann's shoulder with his chakra, so unless he removes it himself or he is killed, no one else can remove it from him. Although it does not give Zann the ability to freely control, create and manipulate any metal around him, it does allow him to change the shape of his arm as he pleases, though he cannot change its mass. For example, he can make it into a thick short blade, or a thin long blade.
See note 1The special ability of the arm is that it lets Zann absorb any katon or fuuton jutsus and convert it into chakra. Any jutsus within that element will immediately be absorbed into chakra for his body if he touches the attack with his arm. (jutsus have to be the same rank or lower than himself, and this has no effect on higher ranked katon or fuuton jutsus)
See note 2Inside the arm are seals for hidden weapons, as well as a cartridge for chakra strings for puppetry. The seals for hidden weapons include kunai, shuriken, senbon and thin sewing needles, as well as 3 barbed wires. The mechanism behind weapon seals is that they materialise a little of Zann's chakra for every projectile and form metal weapons, which can be launched at the enemy. The cartridge for chakra strings allow Zann to control up to 30 puppets with one hand, something impossible with flesh and blood hands.
Because it is made from metal, it is considerably weaker to raiton element attacks as metal conducts electricity. If it comes into contact with electricity then the attack would conduct through his arm and to his body, damaging it, so raiton attacks would instead strengthen if used against him (power is boosted 1 rank). Also, because it is made from living metal, Zann cannot use it against users of that kekkai genkai, as they would be able to manipulate his arm as they please, making it useless against them.
Note 1: Zann can manipulate his arm's shape and defend himself against doton and suiton jutsus of the same rank by creating a defensive shape, but his arm will be damaged and the defence would not work if they were S ranked jutsus. This does not work against any raiton jutsus.
Maximum number of times Zann is able to change the shape of his arm:
Normal state: 10 times
Using curse seal/demon/chakra gates: 20 times
Using any of the 2 at once: 30 times (is damaging to body)
Using all 3 powers: 40 times (extremely damaging to body)
Note 2: Maximum amount of katon/fuuton jutsus absorbed:
D rank: 9
C rank: 8
B rank: 7
A rank: 6
S rank: 5

(It's a crappy image I know, but I couldn't find a better picture)

Zann with his automail right arm