Main Character is the main protagonist of the "Rules of Engagement" series.
Her default name is "Katie", but the player can choose to name her as they wish.
She has brown eyes, tan skin, and brown hair that are customizable with different lengths and hairstyles.
She is sweet, caring, romantic, and always follows the rules. She always tries to help all of her siblings with their inheritance task.
The Main Character meets the Bartender in Book 1, Chapter 1 and can flirt with him. He is one of the three Love Interests in the series; he falls in love with the Main Character throughout Book 1. The Main Character and the Bartender share a love for traveling and adventure. The Bartender punches the Main Character's ex-fiance after he tries to grab her. He proposes to her in Book 2 and the Main Character can choose to marry him at the end of Book 2.
Handsome Businessman (William)
A handsome stranger in a suit saves her from Shane, a bad date at a singles-cocktail mixer. They go on a date in Venice in the next chapter and if you spend diamonds to extend the date, you will be able to kiss him. He sends your main character flowers and you are even able to video chat with him. Finally, he also invites your character on a date in Paris. He proposes to the Main Character in Book 2 and she can choose to marry him at the end of Book 2.
European Guy (Leo)
She meets the European Guy in Athens and even go on a date together. He chooses to go on the cruise with her because he says he couldn't resist her. They can kiss multiple times if the player chooses it. They both share a love of adventure and they often break the rules. The Main Character later finds out that he is the crown prince of Cordonia, a small country near Greece. The European Guy later abdicates the throne because of the Main Character. He is the first to propose to the Main Character in Book 2 and she can choose to marry him at the end of Book 2.
The fiance is her old fiance until she caught him cheating on her with Sabrina. After hearing about the money, he tries to get back with her so they can split the money. He tricks the Main Character into signing a marriage contract and she spends most of Book 2 trying to get out of the marriage. He has not appeared in Book 3.
The Cousin has always been jealous of her and her siblings, because she thinks that Nana loved them more than her. After Nana's death, she now tries to get the whole inheritance for herself by sabotaging her cousins' tasks. Throughout the book, the Main Character can be nice to her or be mean to her.
- She is shown on the cover of "Rules of Engagement, Book 1", "Rules of Engagement, Book 2", "Rules of Engagement, Book 3" and the series spin-off "Rules of Engagement: Newlyweds".
- Main Character is the only character in "Rules of Engagement" for whom the player can choose the look.
- Of all the customizable Main Characters/Your Characters in Choices, this Main Character is the only one confirmed to not be on the LGBT spectrum by default or by choice, as all her love interests are male.
- Her mother is Filipino Chinese and her father is British.
- She and Cousin (Violet) used to be very close friends when they were children.
- In the end of Rules of Engagement: Newlyweds, Chapter 5, it is revealed that she is pregnant with twins.