Haruichi Izumo vs The Looper (Fortnite Battle Royale): who would win?

Haruichi Izumo favored — Slight edge (~55%)

Haruichi Izumo · Kaiju No. 8 · Base

Tier
8-C, up to HIGH 8-C
Attack Potency
Building Level, up to Large Building Level
Speed
Superhuman
Durability
Building Level, up to Large Building Level

The Looper (Fortnite Battle Royale) · Fortnite · Base

Tier
8-C, up to 8-B
Attack Potency
Building Level, up to City Block Level
Speed
Average Human, up to Supersonic+
Durability
Small Building Level+, up to City Block Level

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