The Mountain Sire's Spine is a Mortal Unique zweihander, hunted from The Mountain Sire in the Mortal Arena, always at item level 120. It is one of four Exceptional drops on its list — 2.5% of the Uniques that boss gives up, about 1 in 40 — and every kill rolls the list 5 times. It is built on Sovereign Atlas Zweihander — step 6 of the Atlas Zweihander line, item level 80 and up.

It always rolls the same numbers: +216 Power, −14% Attack Speed, +5% Melee Lifesteal, +44 Power, +18% Stone Damage, +16% Power, +44% Stone Damage, +55% Critical Damage and +32% Attack Speed.

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 The Mountain Sire's Spine — Your Main is attuned to Stone, swings wider and heaps Crumble on every foe; Sunder cracks the ground in a Seismic shockwave, but it winds up 25% slower.

It leans into Stone and Crumble.

Wearing it hands you Charged Overhead and Whirlwind.

“Ask the mountain a question. Duck.”