Wikipedia
Mileena is a player and occasional boss character from the Mortal Kombat series of fighting games. Since her introduction as a palette swap character for Mortal Kombat II in 1993, Mileena has gained significant popularity and became one of the series' most iconic elements.
In the games, Mileena was originally known as a dual sai-wielding assassin in service of the dark emperor of Outworld, Shao Kahn, and an evil twin sister of his beautiful daughter Kitana. However, she was soon revealed to be just a monstrously deformed and mentally unbalanced clone of Kitana, created for Kahn by Shang Tsung. In the later games, Mileena also uneasily serves other masters, namely Shinnok and Onaga, and is a central character to the plot of the game Mortal Kombat: Deception. In the backstory of Mortal Kombat X, Mileena, the sole surviving heir of Shao Kahn, vies for the Outworld throne with warlord Kotal Kahn.
Mileena's traits in the original timeline are traditionally defined by her fierce rivalry with Kitana, as well as her own lust for power and cannibalistic urges. The series' 2011 reboot made her ever more unstable but also very immature, and her relationship to Kitana is more ambiguous. In the various other media in the franchise, Mileena's appearances have been relatively rare and minor as compared to these of Kitana, and she is usually positioned in them as an adversary of Earthrealm champion Sonya Blade. She has often appeared in Mortal Kombat merchandise and was also extensively used to promote later games in the series as its semi-ironic sex symbol.
Gameplay-wise, she is considered a generally strong fighter, including being widely regarded as the best choice in Mortal Kombat II. In relation to her other aspects, Mileena received a diverse and often mixed, largely due to the character's unbalanced deranged personality and conflicting messages from the dualism of her design, but in most cases favorable critical reaction, along with some negative criticism as well.