Maybe an idea for next time?
I always work with (at least) 2 saveslots, so I never can't have such a problem. So I store always a savegame from 1 level lower than my current hero's level. and if he level-up, I overwrite the savegame with the lowest level ... etc, etc ...
That Black Ring Sergeant, is that a L27 enemy? In that case I believe you're in the Mine Tower !
and so you play the "Ego Draconis" version, the version without the add-on (Flames of Vengeance)? I think this because in the newer version you CAN'T going in the Mine Tower(where yo can do a quest for William) anymore BEFORE you take over the Battle Tower (after killing 'Laiken').
[ I play the Dragon Knight Saga (DKS) (on Xbox360) that include two parts: Ego Draconis + Flames of Vengeance ]
