the original series, Gwen had short red hair and green eyes. As she has grown older, her red hair is now long and her green eyes seem to have darkened.
In the series Ben 10, Gwen wore a blue shirt with a cat logo on her chest.
In the first and second seasons of Alien Force she wears a white shirt under a dark blue sweater, black stockings under a black mini skirt, and black high heels. In the third season, she wears a dark red shirt paired with a black vest, gray skinny jeans, and black flats. Her hair is worn in a high ponytail.
In the Ultimate Alien, her outfit is similar to her outfit from the first two seasons of Alien Force, but with a red sweater while her hair still is now slicked back in a ponytail.
Her naive nature is toned down in Alien Force. Gwen is at times shown to be very concerned with things such as her surroundings, the people around her and the ones who she cares about. She is very strong (physically and mentally) and well mannered, despite her inflating sarcasm and ego at certain times. Gwen is a very caring, compassionate person such as shown from her acceptance of Kevin's past and recent action, also saying she does not care about Kevin's appearance.
In episode It's Not Easy Being Gwen, it shows that Gwen takes her education very seriously. Showing to come home late at all hours of the morning and having to wake up at 5:30am in the morning. When waking up so early she does a number of things before going to school. Such as jogging, practice french, school, and afterschool karate classes. Its also presumed that Gwen goes to private school since it shown that her usual clothing are actually a uniform at her school.
Ben 10 (Original Series)Edit
In the original series, Gwen uses her laptop to research any strange people and creatures they might come across. She is a capable gymnast and has had some training in martial arts.
Ben 10: Alien ForceEdit
Gwen is now a black belt (taking classes in Karate), but tends to favor using her powers. She is capable of creating energy constructs for nearly any purpose, usually creating platforms to levitate herself (and others), beams to grab enemies, circular blasts to knock enemies back, projecting beams from her eyes that seem to simulate heat vision, and opening up interdimensional portals.
Her powers and abilities are revealed to be of alien descent; her paternal grandmother, Verdona, is an energy being known as an Anodite; from the distant planet Anodyne, and surprisingly she seems to be the only human descendant who inherited Verdona's powers. Verdona tells Gwen that what she and others originally thought of as "magic" was actually the control of mana, a substance of magic-making Anodites; a magic-wielding race. Verdona offers to take Gwen to her home planet and train her in the immense mystical and magical ways of the Anodites, but Gwen prefers to remain on Earth with Ben and Kevin. She dislikes being called an "energy being", referring to her Anodite heritage as revealed in the episode Paradox.
In Unearthed, an alien creature was able to see her as an Anodite, in which she looked exactly like her paternal grandmother's true form, but slightly shorter.
In the two-part second season finale War of the Worlds when Kevin was threatened by a Highbreed Commander, she released her dormant innermost Anodite self for the first time, and easily defeated the commander with an exceedingly strong powerful burst of pure magenta-pink glowing energy. She was almost overwhelmed by her own power and wanted to defeat the highbreed all on her own before Kevin snapped her out of it by saying " I can't lose you."
During the course of the series she has developed a romantic relationship with Kevin. They have also been shown to have arguments, usually starting with Gwen always trying to force Kevin to "ask her out" and him always answering "Don't push me" (which she once did).
Ben 10: Ultimate AlienEdit
In the sequel that takes place a few weeks later, Gwen is now sixteen years old. Her wardrobe has altered once again, wearing a combination of her outfits from Alien Force. She wears her old outfit from the first two seasons of Alien Force, but instead of a plain dark blue shirt it is now dark red and she also keeps her high ponytail from the third se
In Hit 'Em Where They Live, Zombozo and other villains teamed up to take revenge on the Tennysons and company, and kidnapped Ben's mom Sandra. Enraged, Gwen released her dormant, inner anodite for the second time since, War of the Worlds: Part 2. Whilst Zombozo trembled with fear, Gwen began to grow to a huge height, promising that if one of his teammates (and other notable villains) even bumps into a their families on the street, she would come for them. Petrified, Zombozo screamed off-screen and Gwen saved Sandra. When Kevin asked what happened to Zombozo she simply replied "We came to an understanding" whilst smiling.
In Video Games, she tries out for her driver's license, earning it in the end. In the early episodes of the series, Gwen and Kevin seem to be bickering constantly. Gwen's magenta-violet-purple shields look less see through and have a different design than in Ben 10: Alien Force.
In Ultimate Aggregor, Gwen is seen to have much, much greater skills with mana. In Map of Infinity, it is revealed that Gwen's Anodite powers do not affect Galapagus' species and Aggregor, (with his powers), leaving Gwen vulnerable.
From Map of Infinity onwards, Gwen starts casting spells and reciting spoken incantations again. She is also seen with a Plumbers' suit. She is the only one of the group that can use her powers in the suit, during her attempt to recover the first part of the Map of Infinity, she discovers it was hit by a poison dart and ends up fainting, causing Aggregor to catch the first fragment, but Kevin and Ben save her from near death..
In Absolute Power, Gwen is more determined than ever to save Kevin. Ben disagrees with Gwen, opting to kill him now rather than a last resort. Gwen goes to Max hoping he will disagree about killing Kevin, but her grandfather confirms that killing Kevin is the right decision. Telling Gwen that if she disagrees, she should leave Ben to do it and not get in the way. Gwen leaves, disappointed and angry, ready to take desperate measures she confronts Michael Morningstar for help. Meanwhile, Ben goes off looking for Kevin, who's relentlessly going after anyone he thinks has betrayed him. Just as Kevin beats up Vulkanus, and begins to go after Ben, Gwen stops him, accompanied by Michael. Ben is infuriated by Gwen's alliance, but she makes a deal with Ben, and if her plan does not work, she would not bother him anymore in his decision. Gwen also admits that she promised Michael enough mana in return for his help that will keep him at full strength and power for one year, furthering Ben's anger toward her.
- Both Ben and Kevin's middle names were revealed by Gwen.
- Gwen's DNA was sampled and randomized into the Unitrix creating Eunice.
- According to Verdona in Girl Trouble, Gwen is Verdona's favorite granddaughter and Ben her favorite grandson.