hey.. Laiv... the citadel that priest asks you to check out is, Lord Lovis's tower. and if u r on Sentinel Island i'm sure u've finished with that.
above the place where u meet with Lovis, is another room, with a skeleton trader (who prefers u avoid all existential questions) and in there u'll find a scrying stone... which is what the priest wants to study.
oh and in no part of the game do monsters regenerate. neither do u get exp for endlessly shooting arrows at one that's being healed. u only get xp for killing 'em. it's possible that u managed to kill a monster that was a few levels above u and so, u'd get a lot more exp points for it.
my advice, find the healers/summoners and go for them first. if u r already on Sentinel Island and don't want to restart, go at the higher level villains with u'r bow and stay out of their range. stack up heavy on potions and u'll be leveling in no time!
