Excalibur (5e Equipment)
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Weapon (longsword), artifact (requires attunement by a creature fated to be royalty)
This holy sword was the sword of an ancient king, gifted to him by a celestial of great power. People thought this blade was a legend. They were wrong. They have forgotten that there were many kings that have wielded this blade. There are few who know of this blade, mostly those who want to use it for their own reasons and do very cruel things (e.g., over tax, take other people's women, kill those who annoy them, etc.). The blade is golden in the hands of those who are of good, black for those who are evil.
You gain a +1 to attack and damage rolls made with this magic weapon. If your alignment is good, you deal an extra 3 radiant damage. If your alignment is evil, you deal an extra 3 necrotic damage.
The sword has a special attack. When the wielder says its name and puts both hands on it, it does 4d12 damage and is same as the bonus damage when you hit with the sword (e.g., good = 4d12 damage, radiant damage). It can hit foes in a line of 20 feet (e.g., if there are 10 foes in a row, then the wielder hits all 10), but if the wielder is wounded (10 or lower HP), they can only hit 1 foe, no matter if it is in a line with other monsters. When it hits your foes and it does double damage on the opposite nature (e.g., if you good and you hit something that is evil, the damage is doubled), but afterward you have two levels of exhaustion and can't use the special attack until a day has passed.