Heart

Heart is the main source of power in SHY series.

Overview
The Heart is a recurring term which refers to the pure essence of people. It is said to be the main source of power for both Heroes and Amalareiks through Heart Conversion Bracelets and Stigma's rings respectively. It encompasses not only an individual's emotions, but also their deepest wishes and thoughts. Sveta and Hollow presented the ability to create a kind of domain of a variable size that is controlled by them, which they call Amalareik. Normal people are unable to maintain their mental faculties in there: in the case of Sveta, Natalia and the children were unconscious, and in the case of Hollow, the people of Tokyo were in a state comparable to brainwashing.

Heroes' power also comes from the Heart, where they can convert it into energy from their bracelets by synchronizing their Hearts with the device. Thus, they can quickly transform into their Hero forms and utilize superhuman abilities such as superior strength, speed and endurance, as well as having a range of abilities of their own based on their personality and determination. However, it is made clear that to effectively use one's Heart's abilities, some sort of catalyst is needed. Heroes wear Heart Conversion Bracelets, while Amalareik members wear specific rings made by Stigma. Stigma seems to be the only exception to the rule, not being seen using any catalyst so far.