Eileen

Eileen (aka The Birthday Girl) is usually spoiled and bratty. Despite being 10 years old, she looks and acts half her age.

She has long curly red hair and wears a pink dress with pastel blue sleeves on the top portion of her dress. She also wears a pastel blue hair-bow, a purple and gold cat necklace around her neck, light pink frilly socks, and white Mary Jane shoes. When transforming into Birthday Girl, Eileen's skin becomes green.

She can easily be described as greedy, aggressive, self-centered, immature, and sometimes cruel. To others, she often appears to be an innocent little girl. She will do whatever it takes to get what she wants, using a polite demeanor, big eyes, and a lisping voice, along with the phrase, "Today is my birthday!" Whenever she is denied something she desires, she yells, "Mine, MINE, MINE!" With each yell, she grows taller and turns green until the owner of the coveted item gives it to her out of fear.

She believes that every day is her birthday, which is why she has earned the nickname "Birthday Girl." She often uses this belief as an excuse to receive special treatment from everyone, and it usually works quite well. Similarly, she treats every party as if it's her birthday celebration and considers every cake to be her birthday cake. This behavior greatly annoys Becky, especially because of her lisp, where she replaces the "l" and "r" sounds with "w." For example, she might say, "I wearned my wesson," "Today’s my biwthday!" or "What do bestest-westest fwiends do?"

Eileen has a unique ability to charm those around her, which she skillfully employs to achieve her desires and navigate challenging situations. With a playful belief that every day is a celebration of her birthday, she embraces life with a sense of entitlement and joy. Her philosophy can be succinctly summed up in her mantra: "What's mine is mine, and what's yours is also mine." This outlook reflects her confident and somewhat cheeky demeanor, as she navigates her world with a blend of innocence and a shrewd understanding of human nature. Eileen’s charm often disarms others, allowing her to wiggle out of trouble just as easily as she persuades them to fulfill her wishes.

Despite her usual reluctance to show generosity, there have been moments when she displays a caring side towards others. In "Sonny Days with a Chance of Showers," she notices Captain Huggy Face's disappointment in WordGirl after he believes she will choose Sonny as her new three-legged race partner. In an act of kindness, she offers to be his partner instead. Additionally, in "Say It Again, Eileen," she selflessly saves the last crumpet for Becky, without needing any persuasion from others.