The Fishbuster Sword:

The wielder of this artifact increases their prowess by 1; Once per session increase they may increase it by an additional 1 for a single roll. The secondary part of the Sword is locked behind a 2 progress miniquest with the goal of the quest to make the sword a object of Shinran rule (like a royal crown). It is marked as a good level artifact already for purposes of being lost on death/lost at the moment.