Ben 10: The World's Ultimate Alien Duo

(Ben 10 x OC! Zack Tennyson x CrossHarem!)

Summary: Following on the franchise about the kid hero Ben Tennyson, his twin Zack, his cousin Gwen, and Grandpa Max, as they travel the world during summer vacation. When Ben finds the Omnitrix and Zack finds the Ultimatrix, the mysterious watch that transforms them into 10 different aliens, a world of extraterrestrial superpowers opens up to them, changing their lives forever.

Disclaimer: I don't own anything in this story. They belong to their real respective owners. I only own my OC character. All characters are over 18 yrs old (with the exception of adults) and the girls will not get pregnant.

Rated M for Language and Sexual Content.