Dual Skill

Dual Skill is a term used to refer to a theoretical phenomenon where an esper can have more than one psychic ability.

Principles
Everyone who partakes in the Power Curriculum Program has the potential to manifest an ability of their own, however, only one type of ability can manifest within an esper. For instance an esper who has an ability to specifically control fire cannot control water. An esper having more than one ability has been concluded as a theoretical impossibility, though this does not stop researchers from putting the theory to the test. According to Tsukuyomi Komoe, espers' brains cannot handle too many abilities.

According to Accelerator, the now-defunct Special Ability Institute partook in experiments regarding Dual Skill and used Child Errors in their experiments. Anti-Skill – specifically Yomikawa Aiho's team – however caught up with the facility and dismantled it.

It is later revealed that if Takitsubo Rikou ever become a Level 5, her ability would encompass the control of espers' Personal Realities themselves, allowing for Dual Skill to exist.