Minus Energy (マイナスエネルギー Mainasu Enerugī) is a form of dark energy that exists throughout the multiverse. This energy can be created from negative emotions like hate, greed, and jealousy. While the threat of Minus Energy is usually negligible when the universe is at peace, sudden increases in Minus Energy as a result of negative experiences and concentrations of negative emotions can result in the creation of Minus Energy Monsters, a unique class of Kaiju whose existence is intertwined with that of the energy itself.
Minus Energy was first introduced as an energy source in Ultraman 80. This energy was emitted from many characters and allowed the creation of several Kaiju. Many later installments to the Ultraman Series have villains use Minus Energy as empowerment for their creations.
Yapool is a prime manipulator of Minus Energy, and it is later revealed that his body is comprised of this energy. As Yapool's grudge against the Ultras is an example of an phenomenon which can generate Minus Energy, it is possible that this forms part of the sequence that has rendered Yapool capable of reviving himself after each defeat.
A noteworthy location is Planet Tenebris in Nebula M78. The planet has an extremely high concentration of Minus Energy.
- Monster Creation: Large amounts of Minus Energy is able to create monsters. Sometimes the created monster would use a physical medium as a vessel, as seen with Delusion Ultraseven.
- Empowerment: Minus Energy is able to be used to empower other beings.