When he is really mad.
you can use an action replay code to get all the characters or you go to the summon sheet put in a code to grt a misson called Extreme Battle where you fight nine tailed naruto(kyuubi naruto) and sasuke in his second form and if you win you get the nine tailed spirit so naruto can turn in to kyuubi naruto in battle.
Um...O.o No. Kyuubi is the title of the bijuu sealed inside of Naruto. Naruto's mother was Uzumaki Kushina.
Chapter 299 was the first time Naruto went kyuubi.
There is a Kyuubi Naruto on Naruto Arena. You must complete a certain Mission first. I'm pretty sure it's B-rank.
naruto father : the 4th hokage
Kyuubi
Yup. Because of the seal, Naruto doesn't have access to all of Kyuubi power and Kyuubi can easily regenerate all his chakra. He probably has other tricks up his sleeve.
the kyuubi is the nine tailed demon fox yodaime sealed within Naruto.
Not necessarily "useless", but he is less powerful without Kyuubi.
you cant
Naruto doesn't turn into a demon at all. He can release the kyuubi's (The kyuubi is a nine tailed demon fox which has enormous powers) chakra and turn into the kyuubi itself and when he does this it has nine stages which eight of those stages have been seen so far. Of course we haven't seen the ninth stage or the Kyuubi would be released from inside naruto and it would take over resulting in naruto's death. These stages have been seen throughout naruto and are in many episodes. But the very first time he used the kyuubi's power when he was fighting Haku in the land of mist.
Naruto is NOT Kyuubi! Get this into your head! He and the demon fox are ENTIRELY different! The villagers know that the fox is sealed into Naruto but they treat him as an outcast, not the hero keeping Kyuubi from getting his revenge on Konohagakure no Sato (Leaf Village)