Sienna ''Squigly'' Contiello

Sienna Contiello, more commonly known as Squigly (JP: スクィグリー), is an undead girl, kept sentient thanks to her family's Parasite, Leviathan. Her parents were Roberto and Selene, the latter of whom was a previous Skullgirl.

In When the Cold Breeze Blows Away, she would be appeared and mentioned that she against the Nazi Order and Irene Engel since they want take her parasite for unknown bio organic experiments in during World War III.

Until USRAC War, she was killed by Black Dahlia again when she was a undead girl, caused the Nazi Order failed take her parasite.

However,she would be respawned and revived once again after her respawning in graveyard when New Central Powers helped her to start her revenge by killing Black Dahlia and destroy Medici Mafia after Treaty of Wernara and Vitale's death.

She got very powerful strength,undead power and undead control ability from New Central Powers that she joined New Central Powers for take her revenge on kill Black Dahlia,which caused her become third enemy girl of Ms. Chalice and Inkwell Isle Girls, including Ruby Ramirez and the Preschool Girls in during the USRAC War, that she was allied girl of New Central Powers after Treaty of Wernara and Vitale's death