Sisilia is a new unit introduced in Metal Slug Attack.
A member of the Ptolemaic Army, Sisilia uses her signature trumpet to motivate her fellow comrades to victory. Veronica seems to have influenced her decision into joining the Army, though she doesn't feel guilty about it.
She rides alongside her comrades on the battlefield on her bike. It is assumed that she is not old enough to use a motorcycle. Like Rumi and Madoka, if the battlefield becomes too dangerous for her, she will run away.
Sisilia is first seen in the Extra Ops "Bicycle Maiden", where she accompanies Veronica in dealing with the Skull Hermit. At the conclusion of this Extra Ops, she calms down the Skull Hermit and its smaller hermits with her trumpet, which they seem to enjoy.