The Morrigan vs Ghoul: who would win?

The Morrigan favored — Slight edge (~55%)

The Morrigan · Assassin's Creed · Base

Tier

9-A, up to HIGH 8-C

Attack Potency

Small Building Level+, up to Large Building Level

Speed

Superhuman, up to Supersonic

Durability

Large Building Level

Ghoul · Dungeons & Dragons · Abyssal Ghoul

Tier

8-C

Attack Potency

Street Level, up to Island Level

Speed

Subsonic, up to High Hypersonic+

Durability

Wall Level, up to Small City Level

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