Any reason not to add a "Looking Glass icon" to indicate you can mouse over potential slaves to indicate you can see more? For intuitive reasons.
Large Mana Numbers on Front enemies tend to Mix into HP numbers on back enemies, perhaps there could be a better way to display, or atleast adjust the spacing so double digit numbers don't over lap, and perferably tripple digit numbers don't. Polishing for a later game stage though, Adjusting the over all size of the combat window and spacing would probably be enough.