Aristoi is a 1993 science-fiction novel by Walter Jon Williams.
It describes a technologically advanced. society ruled by "Aristoi", a superior class of humanity. One feature is that people can control daimones, separate sub-personalities within their mind which can operate without requiring attention from their main 'self'. In virtual reality these can even be manifested as distinct individuals.
Williams sometimes uses the device of splitting the text into two columns, one describing the real world, one describing the hero's virtual interactions with his daimones.
(ISBN 0812514092)
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