Frostmourne (5e Equipment)
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Weapon (greatsword), legendary (requires attunement)
A runeblade that hungers for victims, frostmourne is a forgotten relic. Growing with the souls it devours, it also takes a part of the wielders own soul.
Hunger Unending As you slay foes and consume their souls, the blade grows stronger. Beginning at level 1, it gains a +1 bonus to all attack and damage rolls. Beginning at level 5, it gains a +2 bonus to all attack and damage rolls. Beginning at level 10, it gains +3 bonus to all attack and damage rolls. Beginning at level 15, it gains a +4 bonus to all attack and damage rolls.
Icy Death The icy touch of the soul fragments remain on the edge of this blade, reducing the speed of creatures hit by 5 feet for 1d4 hours. Beginning at level 10, the sword also deals 1d4 bonus cold damage. Beginning at level 15, the sword deals 1d6 bonus cold damage instead, and reduces the speed of creatures hit by 10 feet.
Eternal Emptiness You must make a DC 20 Constitution save at dusk every day to wield this weapon, and resist it's attack against your soul. On failure, you may have your alignment shifted to evil. However, you will stay lawful, neutral, or chaotic. Alternatively, you may take 1d12 necrotic damage per level, and keep your current alignment, at the cost of becoming immune to all healing effects until you are knocked down or become unconscious. If you fall unconscious from this effect more than twice, the sword will forcefully rip parts of your soul off to feed itself. Reduce your maximum HP by 5 every time you suffer this effect. This HP loss is permanent unless your alignment shifts to evil, and you pass a DC 20 Wisdom check to gain dominance over the weapon which has regarded you as weak. After attempting this check, you must complete a long rest before being able to try again. Each failure reduces your maximum HP by 5.