Berserker's Planet: Fred Saberhagen

Berserker III. It is said they came five centuries ago, wreaking destruction upon the galaxy, sterilising planets and laying waste to solar systems. They were the unliving aliens who programme was to expunge the universe of all living matter - they were the berserkers, death-bringers from deep space...Then Karlsen, the demi-god, turned back the onslaught, forcing them out of the known universe - all except one shell-less brain, which lay festering in a small corner of the galaxy, awaiting the rebirth of civilisation which it would then enslave...Cover art by Peter Jones.