-----
Noire, Sakura, and Sugar, the main robots of the house and who were already considered as members of the Vampire Family after they acquired Blood Core Batteries, enhanced versions of Mana Core Batteries that could self-upgrade themselves, giving various power such as body self-modification, magic material absorption, and even the ability to wield an attribute of magic which they developed into Abilities.
And as they consumed more materials, they grew even stronger.
Noah felt like they were even developing Souls of their own, and that they could perhaps one day be benefited by the System if they kept developing such souls or something.
And even if not, they were already plenty strong and could keep advancing at the side of Noah and everyone else by consuming magic materials and dropped items from Dungeon Monsters.
However, for now, Noah was giving them the task of accompanying Clementina into low-ranked Dungeons, as they could enter weaker dungeons unlike them.
Check "The Protagnist's Sister Is Actually the Strongest"!