Gwendolyn Tennyson was originally Ben 10,000 and Kai Green's daughter and Ken's sister.
In Ben 10,000, Gwendolyn appeared during the battle between Vilgax, the 10-year old Ben, and Ben 10,000. The reason for this is unknown as Ken 10 is set 12 years after the episode Ben 10,000 so she would not have been born or would have been a baby.
In Ken 10, Gwendolyn was seen at Ken's 10th birthday party.n Tennyson was originally Ben 10,000 and Kai green's daughter and ken's sister
- According to Dwayne McDuffie, Gwendolyn and her brother were named after Ben's cousins, Gwen and Ken.
- According to Derrick J. Wyatt, Ben 10,000 does not have Gwendolyn as his daughter in Omniverse.