Karsus vs Ivor: who would win?

Karsus favored — Slight edge (~55%)

Karsus · Dungeons & Dragons · Archwizard of Netheril

Tier

HIGH 6-A, up to 2-A

Attack Potency

Multi-Continent Level, up to Multiverse Level+

Speed

Relativistic+, up to Infinite

Durability

Multi-Continent Level, up to Multiverse Level+

Ivor · Minecraft · With Prep

Tier

5-C, up to HIGH 3-A

Attack Potency

Moon Level, up to High Universe Level

Speed

Average Human, up to Supersonic

Durability

Building Level

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