Ember's abilities are not innate. When he was twenty years old, his mother was killed at home. When identifying her body, he touched her mother's belongings and "saw" death for the first time. The murderer has not yet been caught.
There are a lot of fine white scars on his palms - not burns, but "memory traces" left behind every time he uses his abilities. These scars don't go away, they just build up layer upon layer. In the past five years, there has been no intact skin on his palms.
He knew he was being consumed by this ability. Every time he "burns", he loses a part of "himself" - not necessarily a memory, but maybe a certain emotion, a certain feeling, something that makes him "him". His memos were getting longer and longer, and his diary entries were getting longer and longer, because he was afraid that one day he would wake up and not know who he was.
