Also known as: グウェン・テニスン, グウェン
Cousin of the titular hero Ben Tennyson in Ben 10 and its sequels. Casually known as Gwen, or otherwise known as Gwendolyn Tennyson.
In the original series, she has short Orange Hair and Green Eyes, and wears a Hairclip and a shirt with Raglan Sleeves. In Ben 10: Alien Force, she has Long Hair instead and wears a Sweater with a Skirt. In the post-timeskip sequels, she becomes Kevin's girlfriend.
Due to the popularity of the original series over its sequels, depictions of Gwen are generally of her younger self, rather than her teenage or Future adult self.