Shen (Undead Unluck) vs The Witch-king of Angmar: who would win?

Shen (Undead Unluck) favored — Slight edge (~55%)

Shen (Undead Unluck) · Undead Unluck · Base

Tier

7-A, up to HIGH 7-A

Attack Potency

Mountain Level, up to Large Mountain Level

Speed

Hypersonic+, up to Massively Hypersonic

Durability

Mountain Level, up to Large Mountain Level

The Witch-king of Angmar · Lord of the Rings · During the Siege of Minas Tirith

Tier

7-A

Attack Potency

Mountain Level

Speed

Peak Human, up to High Hypersonic

Durability

Mountain Level, up to Moon Level

A heuristic estimate from normalized VS Battles Wiki stats: tier, attack potency, speed and durability.