This stone — almost ready-made weakening rune for two-handed or one-handed weapons, it remains only to add one of the additional effects of your choice to it:
— a hunter that increases four times the number of achievement points for killing specified types of monsters (excluding bosses) for two-handed weapons and twice for one-handed weapons;
— a wizard that increases four times the number of points in the medal for killing opponents with a spell, using a spell when killing an enemy, or triggering a passive effect when killing an enemy for a two-handed weapon, and twice for a one-handed weapon;
— Shion's Trident (available from level 7).
In battle, you will receive a weakening rune that suits your level.

Triggering the effect of the weakening rune allows you to get a medal "Virtuoso of blades".