Alexia is the main antagonist from Resident Evil:Code Veronica. She was a product of the Code: Veronica experiment; an artificially created twin born using genetic material taken from the preserved corpse of her great ancestor, Veronica, combined with an artificially strengthened, isolated gene that regulated intelligence. Her other twin being Alfred but he didn't inherit the same level of intelligence as her. The mastermind of the project that birthed them was their own father Alexander whom later was subjected to experimentation by her and Alfred then sealed away. As she succeeded in her field of research with her peers like Wesker and Birkin, she took it upon herself to self experiment using the Veronica virus and to make sure she can adapt to it she sealed herself away for 15 years, hoping to awaken and prove her superiority as "Queen" of her new world.

Alexia has long back-length blonde hair and blue eyes. She wears a long dark purple short-sleeved dress with a violet at the edge of her sleeves and the extended skirt of her dress. She also wears long white gloves and a black choker with a red jewel as her pendant and walks in black shoes. After transforming, her skin turns grey with dark roots covering her right arm, left leg and the right side of her face leaving her chest and midriff bare; her eyes are golden yellow in her first transformation.

Due to bonding with the Veronica virus, it grants her a form of pyrokinesis using her blood that she can combust at will when she sprays it at her opponent while transformed as well as forming barbed tentacles that are plant-like in nature. In her later forms while infused with the hive of ants in captivity, she can create small insects to control and attack with and at will, she can materialize bug wings for flight.