The jutsu guaranteed to be used to beat the shit out of a villain. Known users of this jutsu are
Rasengan is the acme of the change of chakra form, a storm of wildly, randomly rotating, concentrated chakra confined in a shape of sphere. When hit by it a normal person's body would be carved and shredded away killing him.
Its a technique beautifully combining randomness of rotating chakra with the perfect shape of a sphere.
Side-effects may include your uchiha team-mate getting butthurt after seeing such power and beauty.
Created by the Legendary Fourth Hokage, Minato after observing a Bijuu Dama, it took him three years to perfect the jutsu. He passed it on to his master Jiraiya and student Kakashi.
Jiraiya took the Rasengan one step further by combining senjutsu chakra with it which massively increased its size surpassing even his body. When used Jiraiya's Rasengan can easily carve out a mountain.
Kakashi couldn't add his chakra nature to Rasengan as that task proved too difficult for him, however he is fully capable of using Rasengan although he is seen putting his left hand on his right while doing it.
Naruto learned the Rasengan from Jiraiya. Due to facing difficulty in rotating chakra in all directions with just one hand he improvised and started using one hand to spin the chakra while the simply releases the chakra. Again after facing a life death situation during his fight with Kabuto he improvised and used a Kage bunshin to use the Rasengan. With these modifications he was able to use Rasengan in just a week after his bet with Tsunade and winning the bet.
Naruto is later on seen being able to use Rasengan with one hand only approximately three years after he first learned it from Jiraiya.
Naruto later teaches Rasengan to Konohamaru who uses his modifications (using kage bunshin for making Rasengan) and defeats Naraka path.
- Oodama Rasengan
- Chou-Oodama Rasengen
- Fuuton RasenShuriken
- Rasengan Barrage
- Planetary Rasengan
- Various movie based rasengans
- and now thanks to naruto power boost, there a shit ton more