In general terms a love slave is a person that is provided into the service of another for romantic purposes; typically for sexual use or for use as a concubine.
Within the League of 20,000 Planets in the time of Lexx however, a love slave refers specifically to a person that has been physically and mentally reprocessed into an idyllic slave. The transformation is performed by a device called a Lusticon which remodels a person's physique to be a stereotype of sexual attractiveness, and brainwashes them to fall in love with whomever they next set eyes upon. Combined with an enhanced libido this assures that the newly modelled love slave will fulfil the desires of their new owner.
It is unknown if love slavery of this type is performed upon both genders, as only the incompletely transformed love slave Zev Bellringer, her reincarnation Xev and a number of love-slaves on the planet Woz are encountered in the series, all of whom are female. In addition, during the series no truly genuine love slaves appear to be encountered, as Xev/Zev is incomplete, those following the Wozzard are reverted to their original appearance, and those in service to the Dark Lady are functioning as guards.
The love slave industry however appears to have been a thriving one, as love slaves are automatically conditioned with an expiry date, which will ultimately cause them to die, possibly as a means to ensure demand or to prevent the problem of aged love slaves.
- The fact that love slavery is one of only two options in the Cluster's penal processing centre, the other being dismemberment for the Protein Bank, would suggest that male love slavery is possible, but this is unconfirmed as male subjects may simply default to dismemberment.