Incomplete Girls

The mysterious hooded figures are strange "other selves" made from the water coming out of Black★Gold Saw's watering can. It is unknown what nature they are of.

Black★Rock Shooter (2012)
Black★Gold Saw creates them by pouring water droplets from a watering can. They sprout from the ground wearing their hoods. In particular, Black★Gold Saw takes an interest in Arata Kohata's "other self".

Black★Rock Shooter breaks into into the area, presumably killing a good chunk of the hooded beings. The survivors look at the sky and chant "coming, coming". BRS attacks Black★Gold Saw but misses, hitting and disabling most of the hooded figures. Black★Rock Shooter approaches Arata's other self and holds her hand up to it. However it trembles in fear and moves back, rejecting the offer. As a result, Black★Rock Shooter beheads the being. In the real world, Arata kneels over in pain. The incident was sensed by Mato Kuroi and Saya Irino.

Black★Gold Saw uses her watering can to summon more hooded beings in her battle against Insane Black★Rock Shooter. Some of these hooded figures had horns, and were armed with pitchforks. They attack Insane Black★Rock Shooter as they chant "Pain, suffering" but she easily defeats them before turning her attention back to Black★Gold Saw.

After Insane Black★Rock Shooter's defeat, the hooded figures, including the one who resembles Arata, come back to life. As a result in Arata regaining her memories and crush on Takuu. The hooded figures now seem to be taller, about the same height as the main characters' other selves, which implies that they have become more powerful.

Trivia

 * Their blood is completely black.
 * They may be incomplete "other selves", as they seem to be significantly weaker than the main cast's "other selves" and they do not seem to have a complete form or personality.
 * In Episode 7, it is implied that most other selves are more advanced or more powerful hooded figures, as during Strength's flashback several other selves are portrayed as hooded figures but with a more developed appearance similar to Strength and B★RS. Additionally, both Strength and B★RS have hoods similar to those of the hooded figures.