Raoul Moat likened himself to King Kong and the Incredible Hulk while on the run from armed police.
The gunman said he struggled to contain his murderous rage and that he "hated himself" because of it.
The feelings could have been triggered by a traumatic childhood in which he was beaten and once saw his mother burn all his toys, an inquest at Newcastle Crown Court heard.
A jury heard the fugitive was paranoid, suspicious, mistrustful of authority figures and blamed other people for his misfortune.
But he was not mentally ill, according to a forensic psychologist brought in to advise expert police negotiators.
Moat shot himself after a tense six hour standoff with armed police, in Rothbury, Northumberland, last year.
The inquest heard Moat was tormented by bad dreams and feelings he struggled to control.
He detailed how they affected him in recordings made on a dictating machine while he was on the run following the shootings of karate instructor Chris Brown, his ex-girlfriend Samantha Stobbart, and Northumbria Pc David Rathband.
He said: "I feel like King Kong when he's right at the top of that building, all messed up, when he's in a real mess.
"I hate myself. I do hate myself.
"It is a part of me. I'm like the Incredible Hulk.
"It is not anger, it is something completely different.
"It is just like a wild animal, and it's been there all my life.
"I'm not sure if my parents put it there or if it has always been there.
"I've had it at the back of my mind and it only ever comes out when I get hurt.
"It is just bonkers.
"A psychologist said it has got something to do with my mother and rejection; I don't know, I don't understand that kind of thing."
He said the violence he'd committed "did not feel real" and likened it to playing the shoot 'em up video game Doom.
And he said when he shot his victims his jaw had been "champing, like he was on ecstasy".
Forensic psychologist John Hughes said the recordings showed Moat "ruminating and rehearsing" what had happened in his mind, as he tried to make a decision on his next move.
The inquest heard how the forensic psychologist had prepared a detailed psychological assessment using information gained from letters seized from the killer's house and from the telephone calls and recordings he made while on the run.
Andrew Straw, cross examining for the Moat family, said throughout his adult life the former doorman had been plagued by nightmares in which he was seven years old and was being chased by monsters.
He asked Mr Hughes whether Moat, who was once prescribed antidepressants for depression, was mentally ill.
Mr Hughes said: "He has hit a point where he is turning things over in his mind and trying to make sense.
"He is using analogies that make sense to him.
"He feels like there is a huge, terrible, angry person in there.
"I did not interpret it to mean in a bigger picture there was any mental illness at that point.
"If you look at his behaviour as a whole there is not the sort of chaotic disorder and failure to plan there would be if he was mentally ill."
He spoke of the need for the expert police negotiators to control the stand-off situation carefully.
He said this would give Moat a sense of control which could prevent an "awful outcome" as they were by that stage dealing with "a suicide intervention" situation.
The inquest, which is expected to last another three weeks, will continue with ten jurors after one member of the jury panel was taken ill today.
Paranoid Moat once admitted that he slept with an axe and crossbow in his bedroom, the inquest heard.
After an assessment, a psychologist wrote to Moat's Newcastle GP to say the patient had CCTV cameras outside his his home and he watched the coverage "a lot of the time".
The letter following a 2006 consultation said: "He feels jumpy all the time, he has concealed an axe and a crossbow in his bedroom, he worries people may break in."
Two years later he completed a questionnaire ahead of a psychological assessment in which he said he had no idea what form the treatment would take.
He wrote: "Knowing my luck it will be all strait-jackets, electricity to the head and a cage."