Mysterious Cubes

— Blast talking about a mysterious cube.

Mysterious Cubes
Information
Type	Transmitter
Creator	God (Presumably)
Owner(s)	God Blast Empty Void
Media
Manga Debut	Chapter 137

These are a series of cubic objects that are used to communicate with "God". Sitch describes them as "OOPart"s.

Overview

Blast explains how the cube operates

According to Blast, the cubes act as transmitters that distort space and allow for communication with "God", who resides in a higher dimension. Anyone who comes in contact with a cube is able to hear the voice of "God" in their head.

A cube was first seen 18 years ago during a flashback of Tatsumaki when she was saved by Blast from a hybrid monster. Another one was also found by Saitama, Manako, and Flashy Flash in the rubble of the Monster Association Headquarters. Blast stated that there are multiple cubes scattered around the world, and that he has been collecting them as a hobby. He has been actively searching for and seizing these mysterious cubes in an attempt to prevent individuals from being bestowed powers by "God".

Abilities

The cubes appear to be extremely heavy, with one causing Flash's arm to become stuck and another sinking into solid rock when dropped by Saitama. Additionally, Manako was unable to lift it back up.

These cube-shaped objects can distort space and time in their vicinity. When Saitama, Flash, and Manako were underground in Z-City near one, Blast stated that their surroundings experienced a slower flow of time compared to other places and advised them to leave quickly. This suggests that the cubes cause a slower passage of time in the vicinity. Additionally, the cubes have the ability to transform humans into Mysterious Beings; by placing their hands on a cube and stating their desires, individuals can receive powers granted by "God". However, if deemed unworthy, they will face "forfeiture," potentially resulting in their demise. The criteria by which "God" determines worthiness remains unclear. By pressing a mysterious cube against his targets, Empty Void can forcibly induce a state of temporary unconsciousness in them. During this state, "God" will attempt to transform the incapacitated individuals into Mysterious Beings.

Plot

Human Monster Saga

Monster Association Arc

One of the cubes appears for the first time during Tatsumaki's flashback as she recalls the events of 18 years ago when she was saved by Blast from a monster. It is revealed that Blast was holding a cube when having a conversation with Tatsumaki at the time.

Saitama dropping the cube

Later, when Saitama and Manako are helping free Flashy Flash, they come across another cube which had pinned Flash's arm down. Saitama inspects it before throwing it away without having any idea what it actually is. As Tatsumaki begins to lift the remains of Monster Association Headquarters into the air, Saitama along with Flash and Manako peer out into the hole expecting to see the underground, only to instead be greeted by a black void, with a mysterious figure sitting prone inside, though the three cannot see it.

Blast teleports the cube to an unknown location

God's voice begins to speak in their heads, saying that if they touch the cube and make a wish, the being will either grant them power, or they will face "forfeiture." Immediately afterward, Blast appears and is relieved to find that the group did not accept God's words. He takes the cube, transferring it through a portal to an unknown location.

Neo Heroes Saga

Psychic Sisters Arc

Shortly after the raid on the Monster Association Headquarters, several S-Class heroes who were involved are summoned to an emergency meeting with Sitch and Sekingar to discuss the unexplained phenomena that were witnessed. In the discussion, "God" is brought up and Flash mentions his encounter with something that could communicate directly into his mind. He mentions Blast in passing and questions Sitch about what he is hiding based on how Blast asked him to send his regards.

Blast and multiple collaborators use some type of device to analyze the cube

Sitch comes clean, admitting that Blast has been fighting "God" for 20 years now and along with some collaborators has been searching for these mysterious cubes that enable communication with "God". During this time, Blast and others had also been collecting and analyzing them. Sitch further states that Blast had a direct encounter with "God" two years ago while battling Elder Centipede and after refusing to accept a transaction of power from "God", the top hero engaged in battle with the mysterious entity and managed to survive.

Ninjas Arc

After Speed-o'-Sound Sonic and Flashy Flash defeat the Heavenly Ninja Party, Empty Void appears and attempts to convert the two ninjas into Mysterious Beings by making them come into physical contact with a mysterious cube. This immediate contact causes the two ninjas to enter a state akin to sleep or unconsciousness, during which "God" tempts them with offers of power.