Thea Stilton is the namesake character in the Thea Stilton books, some a main protagonist but mostly a secondary character in the Thea Sisters series, and one of the main protagonists in the Geronimo Stilton books. She is Geronimo Stilton's younger sister and a special correspondent for The Rodent's Gazette.
Thea is notoriously Geronimo's opposite to a great amount, almost sharing absolutely nothing in common with her brother. Geronimo is reserved, hates traveling, has almost all the common phobias to a near-crippling degree, prefers to think more critically before making a move, hates breaking his status quo, lives for the simple pleasures in everyday life, is polite to a fault, and is always too scared and too nice to stand up for himself; meanwhile Thea is fearless, assertive, unafraid of coming off as nosy if it means finding answers to things, charges headfirst into situations, prefers to strategize in real-time, has nearly no filter when something greatly displeases her, and has an insatiable thirst for adventure. This caters very well to her job as the special correspondent of the Rodent's Gazette, which involves a lot of travel and work off the desk. Her versatility on and off the field has made her a popular person among her peers (to the degree that she tends to get heavy preferential treatment from William Shortpaws), and Geronimo has mentioned having been compared to her frequently and being envious of her skills and personality.
In her book series involving the Thea Sisters, her softer and friendlier side shines through a lot more. Her wild side that Geronimo all too frequently brings up is almost nonexistent, preferring to fulfill a calmer and wise mentor figure role for the Thea Sisters.
Thea is described as being attractive appearance-wise and personality-wise, and as a result a lot of men have had an attraction to her. Not only do Hercule Poirat and Bruce Hyena both have crushes on Thea while Jim Dribbles has had a soft spot & crush on Thea in The Super Cup Face-Off but she also mentions in The Mona Mousa Code and The Lost Letters that she has had multiple boyfriends and countless admirers, respectively. (Geronimo has even said at one point that Thea has had "so many ex-boyfriends that [he'd] need six hands to count them all".) She has used her charisma to her advantage multiple times by sweet-talking her admirers into letting her get through places that would otherwise be inaccessible to her. However, this does have disadvantages, as Thea was tempted into becoming a queen or a princess more than once in the series. Because of her typical dislike for most traits considered feminine in behavior, Thea has always shot down these attempts and offers, and even rejected a typical wild west woman's outfit due to how it restricted her mobility (the only one who did something of this sort) in The Wild, Wild West.
In the television series, Thea is much more composed (if not slightly more aggressive and sarcastic) and more tomboyish than in the books, and typically speaks in a calmer tone than it is implied in the books. She also helps her brother way more on the show and is also less pushy and less teasing towards her brother and treats him more like an equal in the show than she does in the books and has calmed down his nerves on a few occasions such as giving him tea. She also lets Geronimo take the lead in most situations in the show way more than the books. In the books she’s into fashion which is that’s one reason on why she’s a little bit of a girly girl and definitely an adventuress.
