Everyone knows about the Lords of Chaos, who foment madness in the wasteland east of the civilized nations. But few know of the Lords of Law, who dwell far across the sea to the west, for they do not meddle in the affairs of mortal men. Anymore. But long ago they sent a champion to fight chaos, and this was his sword, a sword perfect for that fight.
The Sword of Law does 5 damage, 8 damage if wielded two-handed. The wielder strikes as if they rolled an 11. If it hits a creature of pure chaos, that creature is destroyed if an 11 would fail its save vs. death. The sword is perfectly logical, and will not hesitate to explain why what you're doing is illogical.
