Sisilia is a new character 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, Sisilia is a supply officer rather than a front-line combatant. 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.
She later appears in the Extra Ops "Dancing Brave" where she doesn't like the argument between Veronica and Dragunov over who should be using the PM Union. Later on when they retreat due to Aisha destroying it, she yells at them after they begin arguing again.