|Age|| 10 (Ben 10)|
|Powers and Abilities|
|Relatives||Wes Green (grandfather)|
|Alternate Counterparts||Kai Green (Ben 10,000)|
|Voice Actor||Bettina Bush|
|First Appearance||Benwolf (episode)|
Kai has considerable tracking skills taught to her by her grandfather. In Omniverse, it is revealed that she has been taking Judo lessons, showing considerable skill against trained soldiers of the Forever Knights..
She first appeared doing a spiritual Native American dance in the episode Benwolf. She was Ben's first crush, but she only took interest in him after he started becoming Blitzwolfer because she wanted to, as quoted, "train and tame him". When she admitted to this, Gwen gave her a stern talking to.
Kai appeared in An American Benwolf in London. Working with her grandfather, they find the secret laboratory of Dr. Jekyll, quickly afterwards ambushed by the Forever Knights in their search for Dr. Jekyll's Hyde Formula. While capturing Wes, Kai manages to escape and contacts Ben and his partner Rook Blonko for help. Ultimately, they discovered the hidden location of the legendary Excalibur When removing the blade from its stone seemingly proves impossible even with the Hyde Formula or Ben's strongest aliens, Forever King Chadwick orders his men to kill the enemies. As Ben battles the mutated Forever King, the cave's underground pipes were ruptured and caused a flooding. Convincing the Forever Knights to work together, everyone was able to escape alive.
Ben 10: Omniverse
- An American Benwolf in London (first re-appearance)
Meaning in different languages
- In Hawaiian "Kai" means "Ocean" or "Sea".
- In Maori "Kai" means "Food".
- In Portuguese "Kai" is pronounced "cai" which means "Falls".
- In Romanian "Kai" looks like the word "cai" which means "Horses".
- In Japanese "Kai" means "King". It can also mean "Sea" or "Ocean".
- In Lithuanian "Kai" means "When".
- In Marathi (an Indian language) "Kai" is pronounced "kaay" which means "What".
- In Ken 10 it is seen that Kenny's skin color is a mix of white and native American. According to the pop-up version, Ben would eventually marry Kai in a possible future, and she is Ken's mother.
- In An American Benwolf in London Kai is shown to be the only one able to move the sword Excalibur from it's stone, having grabbed onto it in order to prevent drowning it moved slightly. Also, while still greatly liking Blitzwolfer, she has shown signs of growing interested in Ben for himself, becoming bashful when people imply they are a couple and giving Ben a kiss on the cheek as he leaves.