Awakening

Awakening is the term used when an esper develops a completely new level of power, often manifesting in angelic characteristics, such as wings and, in Accelerator's case, a halo. Not every esper has the potential to awaken, in fact the only ones to have achieved this were the top two espers of Academy City, Kakine Teitoku and Accelerator, although it has been hinted that Kamijou Touma has the potential to awaken.

Index withnessed Accelerator's first incomplete awakening while he was fighting Kihara Amata, and shockedly she thought to herself that the power he used then was so great, that not even a saint would have been able to handle it.

The "awakening" process itself is actually quite simple yet not easily achieved, the power user must have an important revelation; a realization important enough to have an influence in the way the user lives his life. Since the usage of powers is related to personality, the awakening process might be described as similar to "maturing" or "growing up" mentally. Both Kakine and the Accelerator proved that depending on the power the type of revelation that they have the result is completely different even if the person is the same.

Kakine first awakening gave him 3 pairs of wings, when Kakine had a better revelation the wings increased it's side tremendously while keeping their original shape. The basis of Kakine's awakening was revealed to be "Understanding on how ESPer powers works" and "where do they come from".

The Accelerator's first awakening gave him huge black wings which are more like huge blades than wings, in volume 21 when the Accelerator's changes a little his way of thinking, we have that his black devilish wings become completely white and he also gains a halo as well. The basis of Accelerator's awakening was revealed to be related to the determination he has when "fighting between life or dead" as well of his own stance about "killing or not killing" his enemy.