Ideal Energy

Ideal Energy and Kegare are recurrent concepts in Persona 2: Innocent Sin and Persona 2: Eternal Punishment. Like Magatsuhi, they are types of energy generated by human psyches. However, the key difference between Magatsuhi and the two types of energy is the actual generation of the substances; Ideal Energy is generated by dreams and hopes, while Kegare is a highly corruptive, potentially toxic substance generated by guilt and despair.

Enormous quantities of either substance are able to warp reality according to the controller's wishes; however, the process is extremely erratic and volatile, only allowing individuals of extreme power (e.g. Nyarlathotep) to unlock its fullest potential.

In Persona 2: Innocent Sin, the Masquerade's original plan revolved around collection of Ideal Energy to use it in conjuction with Sumaru City's powers to raise Xibalba and create a golden age for humanity. To this purpose, four crystal skulls were used to drain Ideal Energy from selected victims.

Joker-sama used one to drain the energy of anyone who called but did not answer his question, another was given to a junior member of the Masquerade in Kasugayama High School to drain the Ideal Energy of his classmates during the school festival, Prince Taurus used another to drain the assistants to the MUSES concert.The last one was wielded by King Leo and was lost to him during the events of the Sky Museum.

Nyarlathotep switched tactics in the Eternal Punishment timeline, collecting Kegare instead of Ideal Energy through the New World Order through various means, mostly convincing people through various means to assist to Ginji Sasaki's seminar, which was a trap designed to siphon the Kegare of the audience.

The drained substance was collected, and Sasaki was forced to defend it from a violent shootout. Predictably, the Kegare tanks were shattered and he was doused in the contents, transforming him into another victim of the JOKER curse.