Kai Tennyson
General Information
Species 1/2 Human

1/2 Methanosian (dormant)

Home World Earth
Residence Tennyson Household
Age 15/16 - Kai
Affiliations N/A
Occupation(s) Student
Powers and Abilities
Equipment Omnitrix
Relatives Isabelle Tennyson (mother)

Ben Tennyson (father)

First Appearance The Return (Kai)

Kai is the main protagonist in Kai. He first appeared in The Return. He is a Human from the planet Earth. He wields the Omnitrix... albeit after his 16th birthday.


Kai wears a black jacket with green on the end of the sleeves. He has black hair and green eyes. He is quite muscular.


He prides himself on not being like Ben was as a younger child and prefers to be normal rather than be famous with the Omnitrix.

Powers and Abilities

Kai wields the Omnitrix, sent by Ben for his 16th birthday. It is the same Omnitrix which Ben found in 1986 and lost in 1991 at the age of 15.


Kai's weaknesses are the same of a normal human.


Kai was born to parents Ben Tennyson and Isabelle Tennyson on the 25th of January 2000, in London, England, after returning from the First Universal War. Ben was 24, having been born in 1976 and Isabelle was 21. Ben left Isabelle in 2001, noticing that Kai was going to be able to use the Omnitrix. This would put himself and Isabelle in danger, so Ben left to protect his family. As Kai grew up, his Methanosian abilities reduced. It is reported that when he was 5 years old he was able to withstand fire.



He is the son of Ben Tennyson and Isabelle Tennyson.


His father's employee helps him recieve the Omnitrix. His name is Fole.

Love Interests

Not yet.


Not yet.



  • Kai recieves the Omnitrix in the very same campfire that his father, great-grandfather and his cousin once removed went to.


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