Iwao Kuroiwa vs Warp: who would win?

Warp favored — Slight edge (~55%)

Iwao Kuroiwa · Tokyo Ghoul · Base

Tier
LOW 7-C
Attack Potency
Small Town Level
Speed
Massively Hypersonic, up to Massively Hypersonic+
Durability
Small Town Level

Warp · DC · Base

Tier
LOW 7-C
Attack Potency
Small Town Level
Speed
Relativistic
Durability
Small Town Level

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