Mugen

Name: Body Replacement Technique
Rank: E-rank
Element: N/A
Type: Supplementary
Description: This jutsu lets the user quickly switch places with another nearby object, such as a plant (normally a section of a log), an animal, or even another person within reach using the Body Flicker Technique, the moment an attack hits. This creates an optical illusion, making the enemy think the attack was successful. The user can then use this confusion to escape or launch a counter-attack. Exploding tags can be attached to the replacement for an added surprise.
--
Name: Transformation Technique
Rank: E-rank
Element: N/A
Type: Supplementary
Description: This jutsu allows the user to transform either themselves or another object into the appearance of another person, animal, or object.The transformation technique is considered to be among the more difficult E-ranked techniques, since it requires constant emission of chakra while mentally maintaining the form.
--
Name: Clone Technique
Rank: E-rank
Element: N/A
Type: Supplementary
Description: This technique creates intangible copies of the user. The clones are simply illusions and will dissipate when they come into contact with something. The illusions can be seen through by the Byakugan and the Sharingan. A person with normal eyes can also distinguish the clones from the original, since the clones do not have shadows and will not disrupt the area around themselves with their movement (won't kick up dust, crush grass, etc.).
--
Name: Body Flicker Technique
Rank: D-rank
Element: N/A
Type: Supplementary
Description: This jutsu is a high-speed movement technique, allowing a ninja to move short to long distances at an almost untraceable speed.[2] To an observer, it appears as if the user has teleported. A puff of smoke is occasionally used to disguise the user's movements. It is accomplished by using chakra to temporarily vitalise the body and move at extreme speeds. The amount of chakra required depends on the overall distance and elevation between the user and the intended destination.
--
Name: Genjutsu Kai
Rank: D-rank
Element: N/A
Type: Defensive
Description: The ninja stops the flow of chakra in their body, and then applies an even stronger power to disrupt the flow of the caster's chakra.
--
Name: Lightning Release: Four Pillar Bind
Rank: (B-rank)
Element: Lightning
Type: Offensive, Supplementary ; Short to Mid range
Description: Four giant rock pillars are summoned around the enemy, then shoot bolts of lightning, immobilizing the target and possibly doing damage to them.
--
Name: Kage Bushin No Jutsu
Rank: B-Rank
Element: N/A
Type: Supplementary
Description: Similar to the Clone Technique, this jutsu creates clones of the user. Unlike the Clone Technique, these clones are actual copies, not illusions. The user's chakra is evenly distributed among every clone, giving each clone an equal fraction of the user's overall power. The clones are capable of performing jutsu on their own and can even bleed, but will usually disperse after one or two solid blows. They can also disperse on their own. The clones will be created in roughly the same condition as the original.

Shadow clones can't be distinguished from the actual person even by the Byakugan because the clones have the exact same amount of chakra and aren't made from any other substance. In the anime, Sasuke Uchiha claims that the Sharingan can distinguish clones from the original, however various events throughout the series seem to indicate that this is not the case, implying that the Sharingan was merely used to keep track of the original's movements.
--
Name: Multiple Shadow Clone Technique
Rank: A-rank
Element: N/A
Type: Supplementary
Description: This jutsu is essentially a massive version of the Shadow Clone Technique. Instead of a few clones, it creates a few hundred clones (or a number of equal grandeur). This is considered a forbidden jutsu, because it can potentially be dangerous to the person performing it, seeing as how all of the clones are given an equal amount of chakra directly from the user. Naruto learned the technique from the scroll of forbidden seals written by the First Hokage.

Few people are able to use this technique effectively, due to the large amount of chakra it consumes. However, this weakness is not an issue to Naruto, due to his massive chakra reserves. Having such reserves allows him to create hundreds of clones while maintaining a decent supply of chakra in each one. This technique is also used by Naruto to train quickly, since all the clones share their experiences with Naruto, but it causes extreme fatigue with repeated use. Some times in the anime or manga, Naruto does not appear to distinguish between the Multiple and regular variations of the technique, and often simply says "Shadow Clone Technique" regardless of how many clones he uses.
--
Name: Clone Great Explosion
Rank: A-rank
Element: N/A
Type: Offensive ; Short Range
Description: The user lures the target in, using a Shadow Clone as bait. The target, acting according to the principle of "attack to bring down the enemy," falls victim to a powerful explosion. If one can see through the body of the Shadow Clone, it is possible to evade the blast. However, by wrapping it up in trick after trick, the target will be guided into the technique for sure. The size of the explosion is considerably large.

Not much is known about the early days of Mugen but there are a few rumors about it. People say that he was born in a poor family in a village that was far from the tension of the ninja world. It is said that when he was born a spirit had infiltrated his body and since then he was been wandering the world with no purpose except destruction. The truth is that when Takezo was born his eyes were different than all the others and the villagers believed that he was a demon due to his intimidating look. His eyes were that of a beast and since he could walk people did not walk in his way and talked behind his back. Takezo had a tough childhood and his negative emotions were suppressed into his heart, locked inside but bound to break free someday for some reason. That day would soon come.

The last day of Takezo living in the village was the day when the village grew tired of him and he grew tired of them. It all began when he was accused of stealing some yen from the village's most influential man - an importer of goods. His parents took responsibility for his action. Actions he did not commit. The angered villagers beat to death Takezo's parents by throwing stones at them. The whole scene was not something a kid would've wanted to see. He fled with his father's katana and disappeared in the forest where he turned into an animal, at first the forest was safe and the villagers often took it as a shortcut but as time passed and Mugen sharpened his skills for his only purpose to live - avenge the death of his family, the forest was his home and the death of many trespassers.
It had been two years since that day and the village had forgotten about the demonic child until one night the houses lit into flames burning the villagers in their sleep. Takezo had razed the village and slaughtered everyone who was able to escape his house in time from the flames. The avenger did not spare neither children, mothers or old men. From that day on he left the forest searching for a new home and a new purpose.

It took time for Takezo to find a home fitting for him but he found it. Actually it found him. His murderous aura was quickly felt by wandering patrol shinobis of the Blood Village and they were cunning enough to restrain him and take him to the Kage who was to decide Takezo's faith.
The Kage who was intrigued of the boy as he easily found out that this boy was a murderer despite his young age and so he asked about his name. Takezo replied he had no name. And so the Kage named him Mugen and enrolled him in the academy where Mugen found a purpose to live for.
In the Academy he had to be often stopped from slaughtering a fellow student despite his animal-like attitude he showed great potential in ninjutsu and made it his top priority learning ninjutsu rather than wielding the sword. The academy reshaped his beast manners and he became cold, calm and composed. He no longer succumbed to his instincts and was a ninja that everyone would like to hire. A ninja not hesitant to kill but also a ninja that uses his brain cells.

Mugen did not bother forging alliances and social contacts and was fully focused on mastering a jutsu he seemed to favor among the others. The Body flicker jutsu. Along with it he seemed very adept in the lightning element and showed to have immense chakra reserves and chakra control seemed to be easy to handle for the ninja. Mugen was signed with his team on the first chuunin exams by his jounin who was madly in love with bloodshed and had no patience to see Mugen slaughter. His impatience costed the lives of Mugen's teammates but also rose Mugen to fame. It was his first steps on the stage of fame and glory. On the other hand though the chuunin had no purpose of acquiring fame and glory. He wanted power and power he got. Many barriers were unlocked when he was promoted to chuunin. The experience he received during his chuunin-ship was a key factor to his future power level. As he grew in age so did his fame in the village grow and when he became a jounin his mere presence struck fear in the hearts of the villagers of the Blood village and his traits were pointed as role models for all future ninjas of the Blood Village.