Questing in Grendel's Cave is a progression of obtaining runes, building rune stones, using those rune stones to obtain access to quest areas, completing tasks, sometimes-complicated ones, to gain amulets, trading in obtained amulets for Yggdrasil and then attacking and killing Grendel. You must follow these steps to win the game, though in PVP kingdoms you could let other players complete these quests and then kill them and steal their hard work.