An ancient deity bent on the destruction and reconstruction of realities, Cygris (pronounced Cy-gris) the Conqueror is a cruel and heartless Goddess (or God depending on the dimension its in) summoned to Station Square after the Containment Grid is shut off. Her sole purpose is to bring forth the Dimensional Merge, an apocalyptic event that will merge the dimensions she has claimed into one "perfect" kingdom...and she'll crush anyone or anything that gets in her way.

Cygris is vocally depicted as a sinister sounding female, and as a Goddess, she talks loudly as if to assert her authority over lesser creatures. Her character is a parody of Gozer the Gozerian, with some elements of a certain prominent figure in Sonic history sprinkled in (I won't say their name, but if you know Sonic history, you could probably make a good guess.) 

Clip for reference: https://www.youtube.com/watch?v=Cti9SL4GO04

Her voice would be similar in tone and speech, but not an exact copy. If you'd like to wing it and come up with something, by all means, go for it!