A Mascot Character, known as Game Chara in the Japanese version, is an entity created by the "One True Goddess" in order to protect the nations of Gamindustri in the case of a CPUs absence and take the physical form of colored discs. While it is their job to defend, outside of when the Candidates utilize their power for their formation group skill, they seemingly do nothing. It is possible that they possess a passive protection ability that enable their powers to work without actually acting. Particularly White Disc's presence is enough to keep the Killachine's in sealed in Lowee, but leaving the place would undo the seal.
List of Mascot Characters
Each nation has its own respective Mascot Character. So far they have only been shown to exist in the Hyperdimension setting of Hyperdimension Neptunia mk2's universe and so therefore do not appear in the Ultradimension setting of Hyperdimension Neptunia Victory.