Frostwyrm's Tooth is a Nightmare Unique dagger, hunted from Frost Wyrm in the Mortal Arena, always at item level 120. It is one of four ordinary drops on its list — 22.5% of the Uniques that boss gives up, about 1 in 4 — and every kill rolls the list 5 times. It is built on Sovereign Sleetwing Dagger — step 6 of the Sleetwing Dagger line, item level 80 and up.

It always rolls the same numbers: +52 Power, +12% Attack Speed, +14% Frost Damage, +10% Attack Speed, +38% Frost Damage, +29% Attack Speed and +12% Critical Chance.

One Unique drop in 40 is a Mythical copy: the same item carrying 15–25% Mythical Energy that boosts every stat on it and can never be changed; the 15% floor is 10 times as common as the perfect 25%.

On top of that it carries Frostwyrm's Tooth — Your Main hits 35% harder and builds Chill.

It leans into Chill.

Wearing it hands you Knife Toss.

“Winter's opening argument.”