Kaiju

Overview
Kaiju are beast that came and attacked the Land of Water after years of predictions by the priest from the Lost Temple. There are only 4 of these beasts and they can only be controlled and summoned by Aoi Uchiha so far. There are specific things to do to summon them and make a special contract with them in order to summon them.

The Kaiju can talk through their summoner's conscious and no one else can hear or enter their conversation. The Kaiju have a mind of their own but obey to their summoners will once under control by the summoner, if not in control by the summoner, they can do what they want. Aoi Uchiha had a hard time controlling the Kaiju, but after a lot of effort he did it.

The Kaiju have no chakra, all they have is physical attributes, but their physical attributes can compare to something with chakra like a tailed beast. If all 4 Kaiju are combined, it is said that they can match up to 7 tailed beast. The Kaiju can be given chakra, but it has never been tried.

Kujira
Kujira (鯨, Whale) is biggest of all the Kaiju being bigger than a tailed beast. This Kaiju resembles a whale hence its name. Under water this beast is a tank, it can withstand tons of damage, from many things. It is the strongest Kaiju with the strongest defense. It's weight is its attack, and it is said that the Kujura has the strength of 5 tailed beast, though that hasn't been tested yet, it was just a prediction by the priest from the Lost Temple. Also if eaten by the Kujura, you cannot get out unless it spits you out, or Aoi commands it. It has a lot of armor that can hardly be penetrated, it can withstand the force of 2 to 3 tailed best balls, but not without being hurt. An ability of Kujura is that he can suck a large amount of water into his mouth and blow it out, the suction and blow out is very powerful being stronger than the gravitational pull and push from Shinra Tensei and said to be equal to the gravitational pull from Chibaku Tensei. Though again that wasn't tested, just a myth from the priest.

Umihebi
The Umihebi (海蛇, Sea Serpent) is the skinniest of all the Kaiju, and is the fastest of the 4. It moves at incredible speed, that of a beast using chakra to move fast. It can track very good as well, the fins that come from around its face detects electro-magnetic energy from things and can pick it up. Thats not the only thing those fins can do, they are also very sharp, he can swim by you and slice you in half, also his sharp teeth can be used to eat you as well. He is flexible and can use his body to coil around a larger object and his fins can retract and sprout back out to cut the object he is around. The Umihebi has the least armor of all the Kaiju and is mostly an attacking type of Kaiju.

Ebi
The Ebi (蝦, Shrimp)

Same
The Same (鮫, Shark