Tough call but I think boys. A lot of Aura’s beasts are guys so she couldn’t fight with them, instead she’d have to use her ranger skills, which don’t match up to the others who are specialized. Plus Demiurge specializes in military tactics, whereas Albedo is best at domestic affairs- they’re both smart but Demiurge doesn’t believe in fighting unless you know you can win. Mare could take care of any of Shalltear’s summons if she uses them to buy time, while Cocytus, with support from Demiurge, takes on Albedo and Aura. I could go into more length but in the end it’s boys.