The God of the old testament is, to me, the closest thing to absolutely evil. Have you read the book of Job?
The books all came from different sources, times, peoples, but there is a malevolent God in many of them that is truly hard to understand because he's so twisted. It's almost as if ancient man was so traumatized he could only envision a completely fucked creator. The old testament God is so evil, he practically makes no sense. Ancient man was probably bewildered.
The universe being completely indifferent seems obvious. Attempting to give it personality gives it the strangest character of all time. I doubt any person could be as evil as a completely indifferent universe. An indifferent despot would have a similar type of evil character.
There's a lot of bad shit in there, but the book of Job is a good place to start.