Serastial (5e Equipment)
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Weapon (longsword), legendary (requires attunement by a good-aligned creature)
You have a +3 bonus to your attack and damage rolls with this magic weapon. Additionally, this weapon deals an extra 1d6 radiant damage to undead.
Sense of Natures. Serastial knows the alignments of any creatures within ten feet of her.
Turn Evil. When an attack from Serastial lowers an evil-aligned creature to zero hitpoints, the creature must makes a DC 16 Wisdom saving throw. On a success, the creature is reduced to zero hitpoints as normal. On a failed save, the creature is instead reduced to one hitpoint and its alignment is changed from evil to good (e.g., LE becomes LG, NE becomes NG, and CE becomes CG). The creature retains all of its memories, but may now see any previous actions through its new alignment. This feature does not affect constructs, undead, or non-evil aligned creatures. The effects of this feature can only be reversed through the use of a wish spell.