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 seems to take an interest in one that seems to be Arata Kohata's "other self".

However, Black★Rock Shooter breaks into the area, causing many rocks to fall down on many of these beings and for them to look at the sky and chant "coming, coming". She then pursues Black★Gold Saw but her shots missed her, hitting and disabling many of the hooded figures except the one that resembles Arata. Black★Rock Shooter walks up to it and holds her hand up to it, but it continues to tremble, and as a result Black★Rock Shooter ignites her eye-flame and beheads the being, while in the real world, Arata keels over, and Mato Kuroi and Saya Irino sense it.

During Black★Gold Saw's battle with Insane Black★Rock Shooter, she used her watering can to summon several more of them to fight her when the latter cut off the former's sword wielding arm. These hooded figures were armed with various weapons, chanting "pain, suffering" and attacked Insane Black★Rock Shooter but she easily decapitated them all before turning her attention to Black★Gold Saw again.

In the final episode, after Insane Black★Rock Shooter's defeat, the figure resembling Arata comes back to life, along with other hooded figures, and results in Arata regaining her memories of and crush on Takuu.

Trivia

 * They may be incomplete "other selves", as they seem to be significantly weaker than "other selves" seen previously, 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.