This is the number one most powerful Jutsu Haku can perform, and he is also the only ninja known who can perform it. That is, because this skill is both a secret Ninjutsu, and a bloodline limit skill, which means only people with Haku's bloodline can perform it.
A Ninjutsu technique which is a variation of the Baika no Jutsu (Multi-size Technique). With this technique, the ninja increases their burning of calories to boost their chakra enough to increase the size of their entire body and their mass until it is many times larger than normal.
Orochimaru's prized jutsu which he turned his back on Konoha for. This Ninjutsu technique allows Orochimaru to anchor his soul to this world forever by inhabiting the body of another human being. Making eye contact with the new host, he projects his soul into their body.
This Ninjutsu technique uses water as its base for creating the clones. Each clone is one tenth as powerful as the ninja using it and has a limited range it can move away from its creator. Like the Kage Bunshin no Jutsu (Shadow Clone Technique), this clone can attack.
A Mokudon (wood type) Ninjutsu technique where the ninja uses their chakra to create the sapling of a great tree, and then continues to use their chakra to feed the root of the sapling. It grows, twists and winds through solid obstacles, and wraps around the ninja's enemy.
A Ninjutsu technique where the ninja inhales deeply and then exhales a vicious stream of wind and sand capable of holding back a small army of ninjas. Very powerful if the being using it is of great size.
