Wesker's partner during the events of RE5. Although her tendency to look down on others due to her good looks led many to consider her nothing more than the spoiled daughter of an elite family, her razor-sharp intellect, unstoppable ambition, and business sense and genetic engineering knowledge inherited from her father, enabled her to climb to the very top as director of the African branch of Tricell. While she aspired to rule as the queen of the new world that would follow the completion of the Uroboros project, Wesker, her king-to-be, infected her with the Uroboros virus. Having been simply used and discarded by Wesker, it is hard not to feel at least some sympathy for her.
As can be seen from the image above, during development, Excella was originally the Tricell Africa director's secretary. While she isn't named directly, the Global Pharmaceutical Consortium's special auditor who appears in the Japan-only RE: Revelations pre-order bonus DVD, Revelations Report, is believed to be Excella.