Karthus vs R-System: who would win?

Karthus favored — Slight edge (~55%)

Karthus · League of Legends · Pentakill Karthus

Tier

HIGH 6-A

Attack Potency

Multi-Continent Level

Speed

Subsonic

Durability

Multi-Continent Level

R-System · Fairy Tail · Base

Tier

HIGH 6-A

Attack Potency

Multi-Continent Level

Speed

Unknown

Durability

Island Level

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