The "Otherworld" is the main setting of the story of the Black★Rock Shooter OVA and the Black★Rock Shooter anime. Black★Rock Shooter and other characters live in this realm, and the bizarre landscape is a witness to constant fighting between its denizens.
The true name for this realm is not yet disclosed, and to aid in reference, will be called "Otherworld".
- It is possible that the Otherworld is the world of "Hazama" in the Innocent Soul manga.
- In the 2012 anime, it is heavily implied to be the "world of many colors" mentioned in the Li'l Bird Li'l Bird Colorful Colors book.
- While in the 2012 anime, the Otherworld is primarily referred to in terms of "the other world" or "that other world", the website occasionally uses the term "imaginary world" (虚の世界 kyo no sekai). However, since it always appears in quotes, it can be interpreted as a temporary name, and thus the true name of this world remains undetermined.
- It can be implied that the design of each world represents a certain emotion that a certain main character is trapped in. For example, Strength's world represented by a Rubik's cube in motion of being solved, implying one being trapped and unable to escape. Black★Gold Saw's world implies desperation and sadness, Chariot's world implies desire and stubbornness, and Dead Master's world implies despair and rejection. Black★Rock Shooter's world while serving as an antithesis represents a blinded view as well as the concept of absorbing all the negative emotions.
- The merging of the worlds as seen in the anime represents the absorbing and integrating of all emotions into one world, hence giving it completion.
- In the OVA, some places of the Otherworld that Black★Rock Shooter walks through resemble certain scenes from the Black★Rock Shooter PV.