The Looper (Fortnite Battle Royale) vs Iharu Furuhashi: who would win?

Iharu Furuhashi favored — Slight edge (~55%)

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

Iharu Furuhashi · Kaiju No. 8 · Base

Tier
8-C, up to 7-A
Attack Potency
Building Level, up to Mountain Level+
Speed
Superhuman, up to High Hypersonic+
Durability
Building Level, up to Mountain Level+

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